Methods and apparatus for lancet actuation

ABSTRACT

A lancet driver is provided wherein the driver exerts a driving force on a lancet during a lancing cycle and is used on a tissue site. The driver comprises of a drive force generator for advancing the lancet along a path into the tissue site, and a sensor configured to detect lancet position along said path during the lancing cycle.

[0001] The present application is a continuation-in-part of and claimsthe benefit of priority from commonly assigned, co-pending U.S. patentapplication Ser. No. /______, (Attorney Docket No. 38187-2593) filedSep. 4, 2002 (US case for—2558 PC); U.S. patent application Ser. No.10/127,395, (Attorney Docket No. 38187-2551) filed Apr. 19, 2002, andU.S. patent application Ser. No. /______, (Attorney Docket No.38187-2594) filed (US case of—2551B PC ). This application is related tocommonly assigned, co-pending U.S. patent application Ser. No. /_____,(Attorney Docket No. 38187-2595) filed Sept. 5, 2002. The completedisclosure of all applications listed above are incorporated herein byreference for all purposes.

BACKGROUND OF THE INVENTION

[0002] Lancing devices are known in the medical health-care productsindustry for piercing the skin to produce blood for analysis.Biochemical analysis of blood samples is a diagnostic tool fordetermining clinical information. Many point-of-care tests are performedusing whole blood, the most common being monitoring diabetic bloodglucose level. Other uses for this method include the analysis of oxygenand coagulation based on Prothrombin time measurement. Typically, a dropof blood for this type of analysis is obtained by making a smallincision in the fingertip, creating a small wound, which generates asmall blood droplet on the surface of the skin.

[0003] Early methods of lancing included piercing or slicing the skinwith a needle or razor. Current methods utilize lancing devices thatcontain a multitude of spring, cam and mass actuators to drive thelancet. These include cantilever springs, diaphragms, coil springs, aswell as gravity plumbs used to drive the lancet. Typically, the deviceis pre-cocked or the user cocks the device. The device is held againstthe skin and the user, or pressure from the users skin, mechanicallytriggers the ballistic launch of the lancet. The forward movement anddepth of skin penetration of the lancet is determined by a mechanicalstop and/or dampening, as well as a spring or cam to retract the lancet.Such devices have the possibility of multiple strikes due to recoil, inaddition to vibratory stimulation of the skin as the driver impacts theend of the launcher stop, and only allow for rough control for skinthickness variation. Different skin thickness may yield differentresults in terms of pain perception, blood yield and success rate ofobtaining blood between different users of the lancing device.

[0004] Success rate generally encompasses the probability of producing ablood sample with one lancing action, which is sufficient in volume toperform the desired analytical test. The blood may appear spontaneouslyat the surface of the skin, or may be “milked” from the wound. Milkinggenerally involves pressing the side of the digit, or in proximity ofthe wound to express the blood to the surface. In traditional methods,the blood droplet produced by the lancing action must reach the surfaceof the skin to be viable for testing.

[0005] When using existing methods, blood often flows from the cut bloodvessels but is then trapped below the surface of the skin, forming ahematoma. In other instances, a wound is created, but no blood flowsfrom the wound. In either case, the lancing process cannot be combinedwith the sample acquisition and testing step. Spontaneous blood dropletgeneration with current mechanical launching system vanres betweenlauncher types but on average it is about 50% of lancet strikes, whichwould be spontaneous. Otherwise milking is required to yield blood.Mechanical launchers are unlikely to provide the means for integratedsample acquisition and testing if one out of every two strikes does notyield a spontaneous blood sample.

[0006] Many diabetic patients (insulin dependent) are required toself-test for blood glucose levels five to six times daily. The largenumber of steps required in traditional methods of glucose testingranging from lancing, to milking of blood, applying blood to the teststrip, and getting the measurements from the test strip discourages manydiabetic patients from testing their blood glucose levels as often asrecommended. Tight control of plasma glucose through frequent testing istherefore mandatory for disease management. The pain associated witheach lancing event further discourages patients from testing.Additionally, the wound channel left on the patient by known systems mayalso be of a size that discourages those who are active with their handsor who are worried about healing of those wound channels from testingtheir glucose levels.

[0007] Another problem frequently encountered by patients who must uselancing equipment to obtain and analyze blood samples is the amount ofmanual dexterity and hand-eye coordination required to properly operatethe lancing and sample testing equipment due to retinopathies andneuropathies particularly, severe in elderly diabetic patients. Forthose patients, operating existing lancet and sample testing equipmentcan be a challenge. Once a blood droplet is created, that droplet mustthen be guided into a receiving channel of a small test strip or thelike. If the sample placement on the strip is unsuccessful, repetitionof the entire procedure including re-lancing the skin to obtain a newblood droplet is necessary.

SUMMARY OF THE INVENTION

[0008] In one aspect of the present invention, a lancet driver isconfigured to exert a driving force on a lancet during a lancing cycleand is used on a tissue site. The driver comprises of a drive forcegenerator for advancing the lancet along a path into the tissue site,and a sensor configured to detect lancet position along the path duringthe lancing cycle.

[0009] In one embodiment of the present invention, a lancet driver isconfigured to exert a driving force on a lancet and to be used at atissue site during a lancing cycle. The driver comprises of avoice-coil, drive force generator, a processor coupled to the driveforce generator capable of changing the direction and magnitude of forceexerted on the lancet during the lancing cycle, and a position sensorconfigured to detect lancet position during the lancing cycle. Althoughnot limited to the following, the voice coil may be a cylindrical coilthat goes around the magnet. The voice coil generator may be linear witha flat coil.

[0010] In another embodiment of the present invention, a lancet driveris configured to exert a driving force on a lancet during a lancingcycle and to be used on a tissue site. The driver comprises of avoice-coil, drive force generator and a processor coupled to the driveforce generator capable of changing the direction and magnitude of forceexerted on the lancet during the lancing cycle. The processor actuatesthe drive force generator to drive the lancet at velocities in time thatfollow a selectable lancing velocity profile.

[0011] In a further embodiment of the present invention, a lancet driveris configured to exert a driving force on a lancet during a lancingcycle and used on a tissue site. The driver comprises of a housing, adrive force generator; and a processor coupled to the drive forcegenerator capable of changing the direction and magnitude of forceexerted on the lancet during the lancing cycle. The driver furtherincludes a position sensor configured to detect lancet position duringthe lancing cycle and a human interface on the housing providing atleast one output.

[0012] In a still further embodiment of the present invention, a bodyfluid sampling device is configured to exert a driving force on a lancetduring a lancing cycle and used on a tissue site. The device comprisesof a drive force generator suitable for actuating the lancet along apath towards the tissue site, into the tissue site, and then back out ofthe tissue site. The lancet penetrates to a depth in the tissue sitesufficient to draw body fluid from the tissue site for sampling. Thedevice further includes a closed feedback control loop for controllingthe drive force generator based on position and velocity of the lancet.

[0013] In another embodiment of the present invention, a body fluidsampling device is provided for use at a tissue site on a patient. Thedevice comprises a drive force generator; a processor coupled to thedrive force generator capable of changing the direction and magnitude offorce exerted on the lancet during the lancing cycle, and a positionsensor configured to detect lancet position during the lancing cycle.The drive force generator actuates the lancet along a one directional,linear path towards the tissue site, into the tissue site, and then backout of the tissue site. The lancet penetrates to a depth in the tissuesite and pauses for a controlled dwell time while in the tissue site.The dwell time may be sufficient to draw body fluid toward a woundchannel created by said lancet.

[0014] In another embodiment of the present invention, a body fluidsampling device is provided for use at a tissue site on a patient. Thedevice comprises a voice-coil, drive force generator and a processorcoupled to the drive force generator capable of changing the directionand magnitude of force exerted on the lancet during the lancing cycle.The device further includes a position sensor configured to detectlancet position during the lancing cycle. The drive force generator hasa magnetic member and a drive coil creating a magnetic field so that thedrive coil magnetically attracts the magnetic member. The drive coil maybe configured to only partially encircle said magnetic member.

[0015] In another embodiment of the present invention, a body fluidsampling device is provided for use at a tissue site on a patient. Thedevice comprises of a voicecoil, drive force generator and a processorcoupled to the drive force generator capable of changing the directionand magnitude of force exerted on the lancet during the lancing cycle.The device further includes a position sensor configured to detectlancet position during the lancing cycle and a mechanical damperdisposed to minimize oscillation of the lancet in the tissue site whenthe lancet reaches an end point of its penetration stroke into thetissue site.

[0016] In another embodiment of the present invention, a body fluidsampling device is provided for use on a tissue site. The device furtherincludes a voice-coil, drive force generator and a processor coupled tothe drive force generator capable of changing the direction andmagnitude of force exerted on the lancet during the lancing cycle. Thedevice may also include a position sensor configured to detect lancetposition during the lancing cycle and a lancet coupler for removablycoupling the lancet to said drive force generator.

[0017] In another embodiment of the present invention, a body fluidsampling device is provided for use on a tissue site. The devicecomprises of a housing, a drive force generator, and a processor coupledto the drive force generator capable of changing the direction andmagnitude of force exerted on the lancet during the lancing cycle. Thedevice may further include a position sensor configured to detect lancetposition during the lancing cycle, a human interface, or possiblyinclude a glucose analyzing device coupled to said housing. The housingand all elements therein have a combined weight of less than about 0.5lbs.

[0018] In another aspect of the present invention, a method is providedfor sampling body fluid from a tissue site. The method comprises drivinga lancet along a path into the tissue site and using a sensor to detectlancet position along said path into the tissue site. The method mayfurther include stopping the lancet in said tissue site for a controlleddwell time to allow body fluid to gather. In a still further embodimentof the present invention, the method may comprise of driving a lancetalong a path into the tissue site using closed loop feedback to controllancet velocity to follow a selectable lancing velocity profile.

[0019] In another embodiment of the present invention, a method isprovided for sampling body fluids from a patient. The method comprisesusing a human interface on a lancet driver to communicate information tothe patient and actuating the lancet driver to drive a lancet into thepatient in a manner sufficient to obtain the body fluid sample. Thehuman interface may be electrically powered, dynamically changeable (toprovide different signals), or be human readable. The human interfacemay also be used to display current status of a lancet driver or otherinformation.

[0020] A further understanding of the nature and advantages of theinvention will become apparent by reference to the remaining portions ofthe specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIGS. 1-3 are graphs of lancet velocity versus position forembodiments of spring driven, cam driven, and controllable forcedrivers.

[0022]FIG. 4 illustrates an embodiment of a controllable force driver inthe form of a flat electric lancet driver that has a solenoid-typeconfiguration.

[0023]FIG. 5 illustrates an embodiment of a controllable force driver inthe form of a cylindrical electric lancet driver using a coiledsolenoid-type configuration.

[0024]FIG. 6 illustrates a displacement over time profile of a lancetdriven by a harmonic spring/mass system.

[0025]FIG. 7 illustrates the velocity over time profile of a lancetdriver by a harmonic spring/mass system.

[0026]FIG. 8 illustrates a displacement over time profile of anembodiment of a controllable force driver.

[0027]FIG. 9 illustrates a velocity over time profile of an embodimentof a controllable force driver.

[0028]FIG. 10 illustrates the lancet needle partially retracted, aftersevering blood vessels; blood is shown following the needle in the woundtract.

[0029]FIG. 11 illustrates blood following the lancet needle to the skinsurface, maintaining an open wound tract.

[0030]FIG. 12 is a diagrammatic view illustrating a controlled feed-backloop.

[0031]FIG. 13 is a graph of force vs. time during the advancement andretraction of a lancet showing some characteristic phases of a lancingcycle.

[0032]FIG. 14 illustrates a lancet tip showing features, which canaffect lancing pain, blood volume, and success rate.

[0033]FIG. 15 illustrates an embodiment of a lancet tip.

[0034]FIG. 16 is a graph showing displacement of a lancet over time.

[0035]FIG. 17 is a graph showing an embodiment of a velocity profile,which includes the velocity of a lancet over time including reducedvelocity during retraction of the lancet.

[0036]FIG. 18 illustrates the tip of an embodiment of a lancet before,during and after the creation of an incision braced with a helix.

[0037]FIG. 19 illustrates a finger wound tract braced with an elastomerembodiment.

[0038]FIG. 20 is a perspective view of a tissue penetration devicehaving features of the invention.

[0039]FIG. 21 is an elevation view in partial longitudinal section ofthe tissue penetration device of FIG. 20.

[0040]FIG. 22 is an elevation view in partial section of an alternativeembodiment.

[0041]FIG. 23 is a transverse cross sectional view of the tissuepenetration device of FIG. 21 taken along lines 23-23 of FIG. 21.

[0042]FIG. 24 is a transverse cross sectional view of the tissuepenetration device of FIG. 21 taken along lines 24-24 of FIG. 21.

[0043]FIG. 25 is a transverse cross sectional view of the tissuepenetration device of FIG. 21 taken along lines 25-25 of FIG. 21.

[0044]FIG. 26 is a transverse cross sectional view of the tissuepenetration device of FIG. 21 taken along lines 26-26 of FIG. 21.

[0045]FIG. 27 is a side view of the drive coupler of the tissuepenetration device of FIG. 21.

[0046]FIG. 28 is a front view of the drive coupler of the tissuepenetration device of FIG. 21 with the lancet not shown for purposes ofillustration.

[0047] FIGS. 29A-29C show a flowchart illustrating a lancet controlmethod.

[0048]FIG. 30 is a diagrammatic view of a patient's finger and a lancettip moving toward the skin of the finger.

[0049]FIG. 31 is a diagrammatic view of a patient's finger and thelancet tip making contact with the skin of a patient's finger.

[0050]FIG. 32 is a diagrammatic view of the lancet tip depressing theskin of a patient's finger.

[0051]FIG. 33 is a diagrammatic view of the lancet tip furtherdepressing the skin of a patient's finger.

[0052]FIG. 34 is a diagrammatic view of the lancet tip penetrating theskin of a patient's finger.

[0053]FIG. 35 is a diagrammatic view of the lancet tip penetrating theskin of a patient's finger to a desired depth.

[0054]FIG. 36 is a diagrammatic view of the lancet tip withdrawing fromthe skin of a patient's finger.

[0055] FIGS. 37-41 illustrate a method of tissue penetration that maymeasure elastic recoil of the skin.

[0056]FIG. 42 is a graphical representation of position and velocity vs.time for a lancing cycle.

[0057]FIG. 43 illustrates a sectional view of the layers of skin with alancet disposed therein.

[0058]FIG. 44 is a graphical representation of velocity vs. position ofa lancing cycle.

[0059]FIG. 45 is a graphical representation of velocity vs. time of alancing cycle.

[0060]FIG. 46 is an elevation view in partial longitudinal section of analternative embodiment of a driver coil pack and position sensor.

[0061]FIG. 47 is a perspective view of a flat coil driver havingfeatures of the invention.

[0062]FIG. 48 is an exploded view of the flat coil driver of FIG. 47.

[0063]FIG. 49 is an elevational view in partial longitudinal section ofa tapered driver coil pack having features of the invention.

[0064]FIG. 50 is a transverse cross sectional view of the tapered coildriver pack of FIG. 49 taken along lines 50-50 in FIG. 49.

[0065]FIG. 51 shows an embodiment of a sampling module which houses alancet and sample reservoir.

[0066]FIG. 52 shows a housing that includes a driver and a chamber wherethe module shown in FIG. 51 can be loaded.

[0067]FIG. 53 shows a tissue penetrating sampling device with the moduleloaded into the housing.

[0068]FIG. 54 shows an alternate embodiment of a lancet configuration.

[0069]FIG. 55 illustrates an embodiment of a sample input port, samplereservoir and ergonomically contoured finger contact area.

[0070]FIG. 56 illustrates the tissue penetration sampling device duringa lancing event.

[0071]FIG. 57 illustrates a thermal sample sensor having a sampledetection element near a surface over which a fluid may flow and analternative position for a sampled detection element that would beexposed to a fluid flowing across the surface.

[0072]FIG. 58 shows a configuration of a thermal sample sensor with asample detection element that includes a separate heating element.

[0073]FIG. 59 depicts three thermal sample detectors such as that shownin FIG. 58 with sample detection elements located near each otheralongside a surface.

[0074]FIG. 60 illustrates thermal sample sensors positioned relative toa channel having an analysis site.

[0075]FIG. 61 shows thermal sample sensors with sample detectionanalyzers positioned relative to analysis sites arranged in an array ona surface.

[0076]FIG. 62 schematically illustrates a sampling module deviceincluding several possible configurations of thermal sample sensorsincluding sample detection elements positioned relative to sample flowchannels and analytical regions.

[0077]FIG. 63 illustrates a tissue penetration sampling device havingfeatures of the invention.

[0078]FIG. 64 is a top view in partial section of a sampling module ofthe tissue penetration sampling device of FIG. 63.

[0079]FIG. 65 is a cross sectional view through line 65-65 of thesampling module shown in FIG. 64.

[0080]FIG. 66 schematically depicts a sectional view of an alternativeembodiment of the sampling module.

[0081]FIG. 67 depicts a portion of the sampling module surrounding asampling port.

[0082] FIGS. 68-70 show in sectional view one implementation of a springpowered lancet driver in three different positions during use of thelancet driver.

[0083]FIG. 71 illustrates an embodiment of a tissue penetration samplingdevice having features of the invention.

[0084]FIG. 72 shows a top surface of a cartridge that includes multiplesampling modules.

[0085]FIG. 73 shows in partial section a sampling module of the samplingcartridge positioned in a reader device.

[0086]FIG. 74 is a perspective view in partial section of a tissuepenetration sampling device with a cartridge of sampling modules.

[0087]FIG. 75 is a front view in partial section of the tissuepenetration sampling device

[0088]FIG. 76 is a top view of the tissue penetration sampling device ofFIG. 75.

[0089]FIG. 77 is a perspective view of a section of a sampling modulebelt having a plurality of sampling modules connected in series by asheet of flexible polymer.

[0090]FIG. 78 is a perspective view of a single sampling module of thesampling module belt of FIG. 59.

[0091]FIG. 79 is a bottom view of a section of the flexible polymersheet of the sampling module of FIG. 78 illustrating the flexibleconductors and contact points deposited on the bottom surface of theflexible polymer sheet.

[0092]FIG. 80 is a perspective view of the body portion of the samplingmodule of FIG. 77 without the flexible polymer cover sheet or lancet.

[0093]FIG. 81 is an enlarged portion of the body portion of the samplingmodule of FIG. 80 illustrating the input port, sample flow channel,analytical region, lancet channel and lancet guides of the samplingmodule.

[0094]FIG. 82 is an enlarged elevational view of a portion of analternative embodiment of a sampling module having a plurality of smallvolume analytical regions.

[0095]FIG. 83 is a perspective view of a body portion of a lancet modulethat can house and guide a lancet without sampling or analyticalfunctions.

[0096]FIG. 84 is an elevational view of a drive coupler having a T-slotconfigured to accept a drive head of a lancet.

[0097]FIG. 85 is an elevational view of the drive coupler of FIG. 84from the side and illustrating the guide ramps of the drive coupler.

[0098]FIG. 86 is a perspective view of the drive coupler of FIG. 84 witha lancet being loaded into the T-slot of the drive coupler.

[0099]FIG. 87 is a perspective view of the drive coupler of FIG. 86 withthe drive head of the lancet completely loaded into the T-slot of thedrive coupler.

[0100]FIG. 88 is a perspective view of a sampling module belt disposedwithin the T-slot of the drive coupler with a drive head of a lancet ofone of the sampling modules loaded within the T-slot of the drivecoupler.

[0101]FIG. 89 is a perspective view of a sampling module cartridge withthe sampling modules arranged in a ring configuration.

[0102]FIG. 90 is a perspective view of a sampling module cartridge withthe plurality of sampling modules arranged in a block matrix with lancetdrive heads configured to mate with a drive coupler having adhesivecoupling.

[0103]FIG. 91 is a side view of an alternative embodiment of a drivecoupler having a lateral slot configured to accept the L-shaped drivehead of the lancet that is disposed within a lancet module and shownwith the L-shaped drive head loaded in the lateral slot.

[0104]FIG. 92 is an exploded view of the drive coupler, lancet withL-shaped drive head and lancet module of FIG. 91.

[0105]FIG. 93 is a perspective view of the front of a lancet cartridgecoupled to the distal end of a controlled electromagnetic driver.

[0106]FIG. 94 is an elevational front view of the lancet cartridge ofFIG. 93.

[0107]FIG. 95 is a top view of the lancet cartridge of FIG. 93.

[0108]FIG. 96 is a perspective view of the lancet cartridge of FIG. 93with a portion of the cartridge body and lancet receptacle not shown forpurposes of illustration of the internal mechanism.

[0109] FIGS. 97-101 illustrate an embodiment of an agent injectiondevice.

[0110] FIGS. 102-106 illustrate an embodiment of a cartridge for use insampling having a sampling cartridge body and a lancet cartridge body.

[0111]FIG. 107 is a schematic showing a lancet driver having a driverforce generator and a sensor according to the present invention.

[0112]FIG. 108 is a schematic showing one embodiment of the lancetdriver using closed loop control.

[0113]FIG. 109 is a schematic showing one embodiment of the lancetdriver using a damper.

[0114]FIGS. 110A and 110B show embodiments of the lancet driver for usewith multiple lancets.

[0115] FIGS. 111-115 illustrate embodiments of a lancet driver with avariety of different interface devices.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

[0116] Variations in skin thickness including the stratum corneum andhydration of the epidermis can yield different results between differentusers with existing tissue penetration devices, such as lancing deviceswherein the tissue penetrating element of the tissue penetration deviceis a lancet. Many current devices rely on adjustable mechanical stops ordamping, to control the lancet's depth of penetration.

[0117] Displacement velocity profiles for both spring driven and camdriven tissue penetration devices are shown in FIG. 1 and 2,respectively. Velocity is plotted against displacement X of the lancet.FIG. 1 represents a displacement/velocity profile typical of springdriven devices. The lancet exit velocity increases until the lancet hitsthe surface of the skin 10. Because of the tensile characteristics ofthe skin, it will bend or deform until the lancet tip cuts the surface20, the lancet will then penetrate the skin until it reaches a full stop30. At this point displacement is maximal and reaches a limit ofpenetration and the lancet stops. Mechanical stops absorb excess energyfrom the driver and transfer it to the lancet. The energy stored in thespring can cause recoil resulting in multiple piercing as seen by thecoiled profile in FIG. 1. This results in unnecessary pain from theadditional tissue penetration as well as from transferring vibratoryenergy into the skin and exciting nerve endings. Retraction of thelancet then occurs and the lancet exits the skin 40 to return into thehousing. Velocity cannot be controlled in any meaningful way for thistype of spring-powered driver.

[0118]FIG. 2 shows a displacement/velocity profile for a cam drivendriver, which is similar to that of FIG. 1, but because the return pathis specified in the cam configuration, there is no possibility ofmultiple tissue penetrations from one actuation. Cam based drivers canoffer some level of control of lancet velocity vs. displacement, but notenough to achieve many desirable displacement/velocity profiles.

[0119] Advantages are achieved by utilizing a controllable force driverto drive a lancet, such as a driver, powered by electromagnetic energy.A controllable driver can achieve a desired velocity versus positionprofile, such as that shown in FIG. 3. Embodiments of the presentinvention allow for the ability to accurately control depth ofpenetration, to control lancet penetration and withdrawal velocity, andtherefore reduce the pain perceived when cutting into the skin.Embodiments of the invention include a controllable driver that can beused with a feedback loop with a position sensor to control the powerdelivered to the lancet, which can optimize the velocity anddisplacement profile to compensate for variations in skin thickness.

[0120] Pain reduction can be achieved by using a rapid lancet cuttingspeed, which is facilitated by the use of a lightweight lancet. Therapid cutting minimizes the shock waves produced when the lancet strikesthe skin in addition to compressing the skin for efficient cutting. If acontrollable driver is used, the need for a mechanical stop can beeliminated. Due to the very light mass of the lancet and lack of amechanical stop, there is little or no vibrational energy transferred tothe finger during cutting.

[0121] The lancing devices such as those whose velocity versus positionprofiles are shown in FIGS. 1 and 2 typically yield 50% spontaneousblood. In addition, some lancing events are unsuccessful and yield noblood, even on milking the finger. A spontaneous blood dropletgeneration is dependent on reaching the blood capillaries and venuoles,which yield the blood sample. It is therefore an issue of correct depthof penetration of the cutting device. Due to variations in skinthickness and hydration, some types of skin will deform more beforecutting starts, and hence the actual depth of penetration will be less,resulting in less capillaries and venuoles cut. A controllable forcedriver can control the depth of penetration of a lancet and henceimprove the spontaneity of blood yield. Furthermore, the use of acontrollable force driver can allow for slow retraction of the lancet(slower than the cutting velocity) resulting in improved success ratedue to the would channel remaining open for the free passage of blood tothe surface of the skin.

[0122] Spontaneous blood yield occurs when blood from the cut vesselsflow up the wound tract to the surface of the skin, where it can becollected and tested. Tissue elasticity parameters may force the woundtract to close behind the retracting lancet preventing the blood fromreaching the surface. If however, the lancet were to be withdrawn slowlyfrom the wound tract, thus keeping the wound open, blood could flow upthe patent channel behind the tip of the lancet as it is being withdrawn(ref. FIGS. 10 and 11). Hence the ability to control the lancet speedinto and out of the wound allows the device to compensate for changes inskin thickness and variations in skin hydration and thereby achievesspontaneous blood yield with maximum success rate while minimizing pain.

[0123] An electromagnetic driver can be coupled directly to the lancetminimizing the mass of the lancet and allowing the driver to bring thelancet to a stop at a predetermined depth without the use of amechanical stop. Alternatively, if a mechanical stop is required forpositive positioning, the energy transferred to the stop can beminimized. The electromagnetic driver allows programmable control overthe velocity vs. position profile of the entire lancing processincluding timing the start of the lancet, tracking the lancet position,measuring the lancet velocity, controlling the distal stop acceleration,and controlling the skin penetration depth.

[0124] Referring to FIG. 4, an embodiment of a tissue penetration deviceis shown. The tissue penetration device includes a controllable forcedriver in the form of an electromagnetic driver, which can be used todrive a lancet. The term Lancet, as used herein, generally includes anysharp or blunt member, preferably having a relatively low mass, used topuncture the skin for the purpose of cutting blood vessels and allowingblood to flow to the surface of the skin. The term Electromagneticdriver, as used herein, generally includes any device that moves ordrives a tissue penetrating element, such as a lancet under anelectrically or magnetically induced force. FIG. 4 is a partiallyexploded view of an embodiment of an electromagnetic driver. The tophalf of the driver is shown assembled. The bottom half of the driver isshown exploded for illustrative purposes.

[0125]FIG. 4 shows the inner insulating housing 22 separated from thestationary housing or PC board 20, and the lancet 24 and flag 26assembly separated from the inner insulating housing 22 for illustrativepurposes. In addition, only four rivets 18 are shown as attached to theinner insulating housing 22 and separated from the PC board 20. In anembodiment, each coil drive field core in the PC board located in the PCBoard 20 and 30 is connected to the inner insulating housing 22 and 32with rivets.

[0126] The electromagnetic driver has a moving part comprising a lancetassembly with a lancet 24 and a magnetically permeable flag 26 attachedat the proximal or drive end and a stationary part comprising astationary housing assembly with electric field coils arranged so thatthey produce a balanced field at the flag to reduce or eliminate any netlateral force on the flag. The electric field coils are generally one ormore metal coils, which generate a magnetic field when electric currentpasses through the coil. The iron flag is a flat or enlarged piece ofmagnetic material, which increases the surface area of the lancetassembly to enhance the magnetic forces generated between the proximalend of the lancet and a magnetic field produced by the field coils. Thecombined mass of the lancet and the iron flag can be minimized tofacilitate rapid acceleration for introduction into the skin of apatient, to reduce the impact when the lancet stops in the skin, and tofacilitate prompt velocity profile changes throughout the samplingcycle.

[0127] The stationary housing assembly consists of a PC board 20, alower inner insulating housing 22, an upper inner insulating housing 32,an upper PC board 30, and rivets 18 assembled into a single unit. Thelower and upper inner insulating housing 22 and 32 are relieved to forma slot so that lancet assembly can be slid into the driver assembly fromthe side perpendicular to the direction of the lancet's advancement andretraction. This allows the disposal of the lancet assembly and reuse ofthe stationary housing assembly with another lancet assembly whileavoiding accidental lancet launches during replacement.

[0128] The electric field coils in the upper and lower stationaryhousing 20 and 30 are fabricated in a multi-layer printed circuit (PC)board. They may also be conventionally wound wire coils. A Teflon®material, or other low friction insulating material is used to constructthe lower and upper inner insulating housing 22 and 32. Each insulatinghousing is mounted on the PC board to provide electrical insulation andphysical protection, as well as to provide a low-friction guide for thelancet. The lower and upper inner insulating housing 22 and 32 provide areference surface with a small gap so that the lancet assembly 24 and 26can align with the drive field coils in the PC board for good magneticcoupling.

[0129] Rivets 18 connect the lower inner insulating housing 22 to thelower stationary housing 20 and are made of magnetically permeablematerial such as ferrite or steel, which serves to concentrate themagnetic field. This mirrors the construction of the upper innerinsulating housing 32 and upper stationary housing 30. These rivets formthe poles of the electric field coils. The PC board is fabricated withmultiple layers of coils or with multiple boards. Each layer supportsspiral traces around a central hole. Alternate layers spiral from thecenter outwards or from the edges inward. In this way each layerconnects via simple feed-through holes, and the current always travelsin the same direction, summing the ampere-turns.

[0130] The PC boards within the lower and upper stationary housings 20and 30 are connected to the lower and upper inner insulating housings 22and 32 with the rivets 18. The lower and upper inner insulating housings22 and 32 expose the rivet heads on opposite ends of the slot where thelancet assembly 24 and 26 travels. The magnetic field lines from eachrivet create magnetic poles at the rivet heads. An iron bar on theopposite side of the PC board within each of the lower and upperstationary housing 20 and 30 completes the magnetic circuit byconnecting the rivets. Any fastener made of magnetically permeablematerial such as iron or steel can be used In place of the rivets. Asingle component made of magnetically permeable material and formed in ahorseshoe shape can be used in place of the rivet/screw and iron barassembly. In operation, the magnetically permeable flag 26 attached tothe lancet 24 is divided into slits and bars 34. The slit patterns arestaggered so that coils can drive the flag 26 in two, three or morephases.

[0131] Both lower and upper PC boards 20 and 30 contain drive coils sothat there is a symmetrical magnetic field above and below the flag 26.When the pair of PC boards is turned on, a magnetic field is establishedaround the bars between the slits of the magnetically permeable iron onthe flag 26. The bars of the flag experience a force that tends to movethe magnetically permeable material to a position minimizing the numberand length of magnetic field lines and conducting the magnetic fieldlines between the magnetic poles.

[0132] When a bar of the flag 26 is centered between the rivets 18 of amagnetic pole, there is no net force on the flag, and any disturbingforce is resisted by imbalance in the field. This embodiment of thedevice operates on a principle similar to that of a solenoid. Solenoidscannot push by repelling iron; they can only pull by attracting the ironinto a minimum energy position. The slits 34 on one side of the flag 26are offset with respect to the other side by approximately one half ofthe pitch of the poles. By alternately activating the coils on each sideof the PC board, the lancet assembly can be moved with respect to thestationary housing assembly. The direction of travel is established byselectively energizing the coils adjacent the metal flag on the lancetassembly. Alternatively, a three phase, three-pole design or a shadingcoil that is offset by one-quarter pitch establishes the direction oftravel. The lower and upper PC boards 20 and 30 shown in FIG. 4 containelectric field coils, which drive the lancet assembly and the circuitryfor controlling the entire electromagnetic driver.

[0133] The embodiment described above generally uses the principles of amagnetic attraction drive, similar to commonly available circularstepper motors (Hurst Manufacturing BA Series motor, or “ElectricalEngineering Handbook” Second edition p 1472-1474, 1997). Thesereferences are hereby incorporated by reference. Other embodiments caninclude a linear induction drive that uses a changing magnetic field toinduce electric currents in the lancet assembly. These induced currentsproduce a secondary magnetic field that repels the primary field andapplies a net force on the lancet assembly. The linear induction driveuses an electrical drive control that sweeps a magnetic field from poleto pole, propelling the lancet before it. Varying the rate of the sweepand the magnitude of the field by altering the driving voltage andfrequency controls the force applied to the lancet assembly and itsvelocity.

[0134] The arrangement of the coils and rivets to concentrate themagnetic flux also applies to the induction design creating a growingmagnetic field as the electric current in the field switches on. Thisgrowing magnetic field creates an opposing electric current in theconductive flag. In a linear induction motor the flag is electricallyconductive, and its magnetic properties are unimportant. Copper oraluminum are materials that can be used for the conductive flags. Copperis generally used because of its good electrical conductivity. Theopposing electrical field produces an opposing magnetic field thatrepels the field of the coils. By phasing the power of the coils, amoving field can be generated which pushes the flag along just below thesynchronous speed of the coils. By controlling the rate of sweep, and bygenerating multiple sweeps, the flag can be moved at a desired speed.

[0135]FIG. 5 shows another embodiment of a solenoid type electromagneticdriver that is capable of driving an iron core or slug mounted to thelancet assembly using a direct current (DC) power supply. Theelectromagnetic driver includes a driver coil pack that is divided intothree separate coils along the path of the lancet, two end coils and amiddle coil. Direct current is alternated to the coils to advance andretract the lancet. Although the driver coil pack is shown with threecoils, any suitable number of coils may be used, for example, 4, 5, 6, 7or more coils may be used.

[0136] The stationary iron housing 40 contains the driver coil pack witha first coil 52 is flanked by iron spacers 50 which concentrate themagnetic flux at the inner diameter creating magnetic poles. The innerinsulating housing 48 isolates the lancet 42 and iron core 46 from thecoils and provides a smooth, low friction guide surface. The lancetguide 44 further centers the lancet 42 and iron core 46. The lancet 42is protracted and retracted by alternating the current between the firstcoil 52, the middle coil, and the third coil to attract the iron core46. Reversing the coil sequence and attracting the core and lancet backinto the housing retracts the lancet. The lancet guide 44 also serves asa stop for the iron core 46 mounted to the lancet 42.

[0137] As discussed above, tissue penetration devices which employspring or cam driving methods have a symmetrical or nearly symmetricalactuation displacement and velocity profiles on the advancement andretraction of the lancet as shown in FIGS. 6 and 7. In most of theavailable lancet devices, once the launch is initiated, the storedenergy determines the velocity profile until the energy is dissipated.Controlling impact, retraction velocity, and dwell time of the lancetwithin the tissue can be useful in order to achieve a high success ratewhile accommodating variations in skin properties and minimize pain.Advantages can be achieved by taking into account that tissue dwell timeis related to the amount of skin deformation as the lancet tries topuncture the surface of the skin and variance in skin deformation frompatient to patient based on skin hydration.

[0138] The ability to control velocity and depth of penetration can beachieved by use of a controllable force driver where feedback is anintegral part of driver control. Such drivers can control either metalor polymeric lancets or any other type of tissue penetration element.The dynamic control of such a driver is illustrated in FIG. 8 whichillustrates an embodiment of a controlled displacement profile and FIG.9 which illustrates an embodiment of a the controlled velocity profile.These are compared to FIGS. 6 and 7, which illustrate embodiments ofdisplacement and velocity profiles, respectively, of a harmonicspring/mass powered driver.

[0139] Reduced pain can be achieved by using impact velocities ofgreater than 2 m/s entry of a tissue penetrating element, such as alancet, into tissue.

[0140] Retraction of the lancet at a low velocity following thesectioning of the venuole/capillary mesh allows the blood to flood thewound tract and flow freely to the surface, thus using the lancet tokeep the channel open during retraction as shown in FIGS. 10 and 11.Low-velocity retraction of the lancet near the wound flap prevents thewound flap from sealing off the channel. Thus, the ability to slow thelancet retraction directly contributes to increasing the success rate ofobtaining blood. Increasing the sampling success rate to near 100% canbe important to the combination of sampling and acquisition into anintegrated sampling module such as an integrated glucose-samplingmodule, which incorporates a glucose test strip.

[0141] Referring again to FIG. 5, the lancet and lancet driver areconfigured so that feedback control is based on lancet displacement,velocity, or acceleration. The feedback control information relating tothe actual lancet path is returned to a processor such as thatillustrated in FIG. 12 that regulates the energy to the driver, therebyprecisely controlling the lancet throughout its advancement andretraction. The driver may be driven by electric current, which includesdirect current and alternating current.

[0142] In FIG. 5, the electromagnetic driver shown is capable of drivingan iron core or slug mounted to the lancet assembly using a directcurrent (DC) power supply and is also capable of determining theposition of the iron core by measuring magnetic coupling between thecore and the coils. The coils can be used in pairs to draw the iron coreinto the driver coil pack. As one of the coils is switched on, thecorresponding induced current in the adjacent coil can be monitored. Thestrength of this induced current is related to the degree of magneticcoupling provided by the iron core, and can be used to infer theposition of the core and hence, the relative position of the lancet.

[0143] After a period of time, the drive voltage can be turned off,allowing the coils to relax, and then the cycle is repeated. The degreeof magnetic coupling between the coils is converted electronically to aproportional DC voltage that is supplied to an analog-to-digitalconverter. The digitized position signal is then processed and comparedto a desired “nominal” position by a central processing unit (CPU). TheCPU to set the level and/or length of the next power pulse to thesolenoid coils uses error between the actual and nominal positions.

[0144] In another embodiment, the driver coil pack has three coilsconsisting of a central driving coil flanked by balanced detection coilsbuilt into the driver assembly so that they surround an actuation ormagnetically active region with the region centered on the middle coilat mid-stroke. When a current pulse is applied to the central coil,voltages are induced in the adjacent sense coils. If the sense coils areconnected together so that their induced voltages oppose each other, theresulting signal will be positive for deflection from mid-stroke in onedirection, negative in the other direction, and zero at mid-stroke. Thismeasuring technique is commonly used in Linear Variable DifferentialTransformers (LVDT). Lancet position is determined by measuring theelectrical balance between the two sensing coils.

[0145] In another embodiment, a feedback loop can use a commerciallyavailable LED/photo transducer module such as the OPB703 manufactured byOptek Technology, Inc., 1215 W. Crosby Road, Carrollton, Tex., 75006 todetermine the distance from the fixed module on the stationary housingto a reflective surface or target mounted on the lancet assembly. TheLED acts as a light emitter to send light beams to the reflectivesurface, which in turn reflects the light back to the photo transducer,which acts as a light sensor. Distances over the range of 4 mm or so aredetermined by measuring the intensity of the reflected light by thephoto transducer. In another embodiment, a feedback loop can use amagnetically permeable region on the lancet shaft itself as the core ofa Linear Variable Differential Transformer (LVDT).

[0146] A permeable region created by selectively annealing a portion ofthe lancet shaft, or by including a component in the lancet assembly,such as ferrite, with sufficient magnetic permeability to allow couplingbetween adjacent sensing coils. Coil size, number of windings, drivecurrent, signal amplification, and air gap to the permeable region arespecified in the design process. In another embodiment, the feedbackcontrol supplies a piezoelectric driver, superimposing a high frequencyoscillation on the basic displacement profile. The piezoelectric driverprovides improved cutting efficiency and reduces pain by allowing thelancet to “saw” its way into the tissue or to destroy cells withcavitation energy generated by the high frequency of vibration of theadvancing edge of the lancet. The drive power to the piezoelectricdriver is monitored for an impedance shift as the device interacts withthe target tissue. The resulting force measurement, coupled with theknown mass of the lancet is used to determine lancet acceleration,velocity, and position.

[0147]FIG. 12 illustrates the operation of a feedback loop using aprocessor. The processor 60 stores profiles 62 in non-volatile memory. Auser inputs information 64 about the desired circumstances or parametersfor a lancing event. The processor 60 selects a driver profile 62 from aset of alternative driver profiles that have been preprogrammed in theprocessor 60 based on typical or desired tissue penetration deviceperformance determined through testing at the factory or as programmedin by the operator. The processor 60 may customize by either scaling ormodifying the profile based on additional user input information 64.Once the processor has chosen and customized the profile, the processor60 is ready to modulate the power from the power supply 66 to the lancetdriver 68 through an amplifier 70. The processor 60 measures thelocation of the lancet 72 using a position sensing mechanism 74 throughan analog to digital converter 76. Examples of position sensingmechanisms have been described in the embodiments above. The processor60 calculates the movement of the lancet by comparing the actual profileof the lancet to the predetermined profile. The processor 60 modulatesthe power to the lancet driver 68 through a signal generator 78, whichcontrols the amplifier 70 so that the actual profile of the lancet doesnot exceed the predetermined profile by more than a preset error limit.The error limit is the accuracy in the control of the lancet.

[0148] After the lancing event, the processor 60 can allow the user torank the results of the lancing event. The processor 60 stores theseresults and constructs a database 80 for the individual user. Using thedatabase 80, the processor 60 calculates the profile traits such asdegree of painlessness, success rate, and blood volume for variousprofiles 62 depending on user input information 64 to optimize theprofile to the individual user for subsequent lancing cycles. Theseprofile traits depend on the characteristic phases of lancet advancementand retraction. The processor 60 uses these calculations to optimizeprofiles 62 for each user. In addition to user input information 64, aninternal clock allows storage in the database 80 of information such asthe time of day to generate a time stamp for the lancing event and thetime between lancing events to anticipate the user's diurnal needs. Thedatabase stores information and statistics for each user and eachprofile that particular user uses.

[0149] In addition to varying the profiles, the processor 60 can be usedto calculate the appropriate lancet diameter and geometry necessary torealize the blood volume required by the user. For example, if the userrequires a 1-5 micro liter volume of blood, the processor selects a 200micron diameter lancet to achieve these results. For each class oflancet, both diameter and lancet tip geometry, is stored in theprocessor to correspond with upper and lower limits of attainable bloodvolume based on the predetermined displacement and velocity profiles.

[0150] The lancing device is capable of prompting the user forinformation at the beginning and the end of the lancing event to moreadequately suit the user. The goal is to either change to a differentprofile or modify an existing profile. Once the profile is set, theforce driving the lancet is varied during advancement and retraction tofollow the profile. The method of lancing using the lancing devicecomprises selecting a profile, lancing according to the selectedprofile, determining lancing profile traits for each characteristicphase of the lancing cycle, and optimizing profile traits for subsequentlancing events.

[0151]FIG. 13 shows an embodiment of the characteristic phases of lancetadvancement and retraction on a graph of force versus time illustratingthe force exerted by the lancet driver on the lancet to achieve thedesired displacement and velocity profile. The characteristic phases arethe lancet introduction phase A-C where the lancet is longitudinallyadvanced into the skin, the lancet rest phase D where the lancetterminates its longitudinal movement reaching its maximum depth andbecoming relatively stationary, and the lancet retraction phase E-Gwhere the lancet is longitudinally retracted out of the skin. Theduration of the lancet retraction phase E-G is longer than the durationof the lancet introduction phase A-C, which in turn is longer than theduration of the lancet rest phase D.

[0152] The introduction phase further comprises a lancet launch phaseprior to A when the lancet is longitudinally moving through air towardthe skin, a tissue contact phase at the beginning of A when the distalend of the lancet makes initial contact with the skin, a tissuedeformation phase A when the skin bends depending on its elasticproperties which are related to hydration and thickness, a tissuelancing phase which comprises when the lancet hits the inflection pointon the skin and begins to cut the skin B and the lancet continuescutting the skin C. The lancet rest phase D is the limit of thepenetration of the lancet into the skin. Pain is reduced by minimizingthe duration of the lancet introduction phase A-C so that there is afast incision to a certain penetration depth regardless of the durationof the deformation phase A and inflection point cutting B which willvary from user to user. Success rate is increased by measuring the exactdepth of penetration from inflection point B to the limit of penetrationin the lancet rest phase D. This measurement allows the lancet toalways, or at least reliably, hit the capillary beds which are a knowndistance underneath the surface of the skin.

[0153] The lancet retraction phase further comprises a primaryretraction phase E when the skin pushes the lancet out of the woundtract, a secondary retraction phase F when the lancet starts to becomedislodged and pulls in the opposite direction of the skin, and lancetexit phase G when the lancet becomes free of the skin. Primaryretraction is the result of exerting a decreasing force to pull thelancet out of the skin as the lancet pulls away from the finger.Secondary retraction is the result of exerting a force in the oppositedirection to dislodge the lancet. Control is necessary to keep the woundtract open as blood flows up the wound tract. Blood volume is increasedby using a uniform velocity to retract the lancet during the lancetretraction phase E-G regardless of the force required for the primaryretraction phase E or secondary retraction phase F, either of which mayvary from user to user depending on the properties of the user's skin.

[0154]FIG. 14 shows a standard industry lancet for glucose testing whichhas a three-facet geometry. Taking a rod of diameter 114 and grinding 8degrees to the plane of the primary axis to create the primary facet 110produces the lancet 116. The secondary facets 112 are then created byrotating the shaft of the needle 15 degrees, and then rolling over 12degrees to the plane of the primary facet. Other possible geometry'srequire altering the lancet's production parameters such as shaftdiameter, angles, and translation distance.

[0155]FIG. 15 illustrates facet and tip geometry 120 and 122, diameter124, and depth 126 which are significant factors in reducing pain, bloodvolume and success rate. It is known that additional cutting by thelancet is achieved by increasing the shear percentage or ratio of theprimary to secondary facets, which when combined with reducing thelancet's diameter reduces skin tear and penetration force and gives theperception of less pain. Overall success rate of blood yield, however,also depends on a variety of factors, including the existence of facets,facet geometry, and skin anatomy.

[0156]FIG. 16 shows another embodiment of displacement versus timeprofile of a lancet for a controlled lancet retraction. FIG. 17 showsthe velocity vs. time profile of the lancet for the controlledretraction of FIG. 16. The lancet driver controls lancet displacementand velocity at several steps in the lancing cycle, including when thelancet cuts the blood vessels to allow blood to pool 130, and as thelancet retracts, regulating the retraction rate to allow the blood toflood the wound tract while keeping the wound flap from sealing thechannel 132 to permit blood to exit the wound.

[0157] In addition to slow retraction of a tissue-penetrating element inorder to hold the wound open to allow blood to escape to the skinsurface, other methods are contemplated. FIG. 18 shows the use of anembodiment of the invention, which includes a retractable coil on thelancet tip. A coiled helix or tube 140 is attached externally to lancet116 with the freedom to slide such that when the lancet penetrates theskin 150, the helix or tube 140 follows the trajectory of the lancet116. The helix begins the lancing cycle coiled around the facets andshaft of the lancet 144. As the lancet penetrates the skin, the helixbraces the wound tract around the lancet 146. As the lancet retracts,the helix remains to brace open the wound tract, keeping the wound tractfrom collapsing and keeping the surface skin flap from closing 148. Thisallows blood 152 to pool and flow up the channel to the surface of theskin. The helix is then retracted as the lancet pulls the helix to thepoint where the helix is decompressed to the point where the diameter ofthe helix becomes less than the diameter of the wound tract and becomesdislodged from the skin.

[0158] The tube or helix 140 is made of wire or metal of the typecommonly used in angioplasty stents such as stainless steel, nickeltitanium alloy or the like. Alternatively the tube or helix 140 or aring can be made of a biodegradable material, which braces the woundtract by becoming lodged in the skin. Biodegradation is completed withinseconds or minutes of insertion, allowing adequate time for blood topool and flow up the wound tract. Biodegradation is activated by heat,moisture, or pH from the skin.

[0159] Alternatively, the wound could be held open by coating the lancetwith a powder or other granular substance. The powder coats the woundtract and keeps it open when the lancet is withdrawn. The powder orother granular substance can be a coarse bed of microspheres or capsuleswhich hold the channel open while allowing blood to flow through theporous interstices.

[0160] In another embodiment the wound can be held open using a two-partneedle, the outer part in the shape of a “U” and the inner part fillingthe “U.” After creating the wound the inner needle is withdrawn leavingan open channel, rather like the plugs that are commonly used forwithdrawing sap from maple trees.

[0161]FIG. 19 shows a further embodiment of a method and device forfacilitating blood flow utilizing an elastomer to coat the wound. Thismethod uses an elastomer 154, such as silicon rubber, to coat or bracethe wound tract 156 by covering and stretching the surface of the finger158. The elastomer 154 is applied to the finger 158 prior to lancing.After a short delay, the lancet (not shown) then penetrates theelastomer 154 and the skin on the surface of the finger 158 as is seenin 160. Blood is allowed to pool and rise to the surface while theelastomer 154 braces the wound tract 156 as is seen in 162 and 164.Other known mechanisms for increasing the success rate of blood yieldafter lancing can include creating a vacuum, suctioning the wound,applying an adhesive strip, vibration while cutting, or initiating asecond lance if the first is unsuccessful.

[0162]FIG. 20 illustrates an embodiment of a tissue penetration device,more specifically, a lancing device 180 that includes a controllabledriver 179 coupled to a tissue penetration element. The lancing device180 has a proximal end 181 and a distal end 182. At the distal end 182is the tissue penetration element in the form of a lancet 183, which iscoupled to an elongate coupler shaft 184 by a drive coupler 185. Theelongate coupler shaft 184 has a proximal end 186 and a distal end 187.A driver coil pack 188 is disposed about the elongate coupler shaft 184proximal of the lancet 183. A position sensor 191 is disposed about aproximal portion 192 of the elongate coupler shaft 184 and an electricalconductor 194 electrically couples a processor 193 to the positionsensor 191. The elongate coupler shaft 184 driven by the driver coilpack 188 controlled by the position sensor 191 and processor 193 formthe controllable driver, specifically, a controllable electromagneticdriver.

[0163] Referring to FIG. 21, the lancing device 180 can be seen in moredetail, in partial longitudinal section. The lancet 183 has a proximalend 195 and a distal end 196 with a sharpened point at the distal end196 of the lancet 183 and a drive head 198 disposed at the proximal end195 of the lancet 183. A lancet shaft 201 is disposed between the drivehead 198 and the sharpened point 197. The lancet shaft 201 may becomprised of stainless steel, or any other suitable material or alloyand have a transverse dimension of about 0.1 to about 0.4 mm. The lancetshaft may have a length of about 3 mm to about 50 mm, specifically,about 15 mm to about 20 mm. The drive head 198 of the lancet 183 is anenlarged portion having a transverse dimension greater than a transversedimension of the lancet shaft 201 distal of the drive head 198. Thisconfiguration allows the drive head 198 to be mechanically captured bythe drive coupler 185. The drive head 198 may have a transversedimension of about 0.5 to about 2 mm.

[0164] A magnetic member 202 is secured to the elongate coupler shaft184 proximal of the drive coupler 185 on a distal portion 203 of theelongate coupler shaft 184. The magnetic member 202 is a substantiallycylindrical piece of magnetic material having an axial lumen 204extending the length of the magnetic member 202. The magnetic member 202has an outer transverse dimension that allows the magnetic member 202 toslide easily within an axial lumen 205 of a low friction, possiblylubricious, polymer guide tube 205′ disposed within the driver coil pack188. The magnetic member 202 may have an outer transverse dimension ofabout 1.0 to about 5.0 mm, specifically, about 2.3 to about 2.5 mm. Themagnetic member 202 may have a length of about 3.0 to about 5.0 mm,specifically, about 4.7 to about 4.9 mm. The magnetic member 202 can bemade from a variety of magnetic materials including ferrous metals suchas ferrous steel, iron, ferrite, or the like. The magnetic member 202may be secured to the distal portion 203 of the elongate coupler shaft184 by a variety of methods including adhesive or epoxy bonding,welding, crimping or any other suitable method.

[0165] Proximal of the magnetic member 202, an optical encoder flag 206is secured to the elongate coupler shaft 184. The optical encoder flag206 is configured to move within a slot 207 in the position sensor 191.The slot 207 of the position sensor 191 is formed between a first bodyportion 208 and a second body portion 209 of the position sensor 191.The slot 207 may have separation width of about 1.5 to about 2.0 mm. Theoptical encoder flag 206 can have a length of about 14 to about 18 mm, awidth of about 3 to about 5 mm and a thickness of about 0.04 to about0.06 mm.

[0166] The optical encoder flag 206 interacts with various optical beamsgenerated by LEDs disposed on or in the position sensor body portions208 and 209 in a predetermined manner. The interaction of the opticalbeams generated by the LEDs of the position sensor 191 generates asignal that indicates the longitudinal position of the optical flag 206relative to the position sensor 191 with a substantially high degree ofresolution. The resolution of the position sensor 191 may be about 200to about 400 cycles per inch, specifically, about 350 to about 370cycles per inch. The position sensor 191 may have a speed response time(position/time resolution) of 0 to about 120,000 Hz, where one dark andlight stripe of the flag constitutes one Hertz, or cycle per second. Theposition of the optical encoder flag 206 relative to the magnetic member202, driver coil pack 188 and position sensor 191 is such that theoptical encoder 191 can provide precise positional information about thelancet 183 over the entire length of the lancet's power stroke.

[0167] An optical encoder that is suitable for the position sensor 191is a linear optical incremental encoder, model HEDS 9200, manufacturedby Agilent Technologies. The model HEDS 9200 may have a length of about20 to about 30 mm, a width of about 8 to about 12 mm, and a height ofabout 9 to about 11 mm. Although the position sensor 191 illustrated isa linear optical incremental encoder, other suitable position sensorembodiments could be used, provided they posses the requisite positionalresolution and time response. The HEDS 9200 is a two channel devicewhere the channels are 90 degrees out of phase with each other. Thisresults in a resolution of four times the basic cycle of the flag. Thesequadrature outputs make it possible for the processor to determine thedirection of lancet travel. Other suitable position sensors includecapacitive encoders, analog reflective sensors, such as the reflectiveposition sensor discussed above, and the like.

[0168] A coupler shaft guide 211 is disposed towards the proximal end181 of the lancing device 180. The guide 211 has a guide lumen 212disposed in the guide 211 to slidingly accept the proximal portion 192of the elongate coupler shaft 184. The guide 211 keeps the elongatecoupler shaft 184 centered horizontally and vertically in the slot 202of the optical encoder 191.

[0169] The driver coil pack 188, position sensor 191 and coupler shaftguide 211 are all secured to a base 213. The base 213 is longitudinallycoextensive with the driver coil pack 188, position sensor 191 andcoupler shaft guide 211. The base 213 can take the form of a rectangularpiece of metal or polymer, or may be a more elaborate housing withrecesses, which are configured to accept the various components of thelancing device 180.

[0170] As discussed above, the magnetic member 202 is configured toslide within an axial lumen 205 of the driver coil pack 188. The drivercoil pack 188 includes a most distal first coil 214, a second coil 215,which is axially disposed between the first coil 214 and a third coil216, and a proximal-most fourth coil 217. Each of the first coil 214,second coil 215, third coil 216 and fourth coil 217 has an axial lumen.The axial lumens of the first through fourth coils are configured to becoaxial with the axial lumens of the other coils and together form theaxial lumen 205 of the driver coil pack 188 as a whole. Axially adjacenteach of the coils 214-217 is a magnetic disk or washer 218 that augmentscompletion of the magnetic circuit of the coils 214-217 during a lancingcycle of the device 180. The magnetic washers 218 of the embodiment ofFIG. 21 are made of ferrous steel but could be made of any othersuitable magnetic material, such as iron or ferrite. The outer shell 189of the driver coil pack 188 is also made of iron or steel to completethe magnetic path around the coils and between the washers 218. Themagnetic washers 218 have an outer diameter commensurate with an outerdiameter of the driver coil pack 188 of about 4.0 to about 8.0 mm. Themagnetic washers 218 have an axial thickness of about 0.05, to about 0.4mm, specifically, about 0.15 to about 0.25 mm.

[0171] Wrapping or winding an elongate electrical conductor 221 about anaxial lumen until a sufficient number of windings have been achievedforms the coils 214-217. The elongate electrical conductor 221 isgenerally an insulated solid copper wire with a small outer transversedimension of about 0.06 mm to about 0.88 mm, specifically, about 0.3 mmto about 0.5 mm. In one embodiment, 32 gauge copper wire is used for thecoils 214-217. The number of windings for each of the coils 214-217 ofthe driver pack 188 may vary with the size of the coil, but for someembodiments each coil 214-217 may have about 30 to about 80 turns,specifically, about 50 to about 60 turns. Each coil 214-217 can have anaxial length of about 1.0 to about 3.0 mm, specifically, about 1.8 toabout 2.0 mm. Each coil 214-217 can have an outer transverse dimensionor diameter of about 4.0, to about 2.0 mm, specifically, about 9.0 toabout 12.0 mm. The axial lumen 205 can have a transverse dimension ofabout 1.0 to about 3.0 mm.

[0172] It may be advantageous in some driver coil 188 embodiments toreplace one or more of the coils with permanent magnets, which produce amagnetic field similar to that of the coils when the coils areactivated. In particular, it may be desirable in some embodiments toreplace the second coil 215, the third coil 216 or both with permanentmagnets. In addition, it may be advantageous to position a permanentmagnet at or near the proximal end of the coil driver pack in order toprovide fixed magnet zeroing function for the magnetic member (Adamsmagnetic Products 23A0002 flexible magnet material (800) 747-7543).

[0173]FIGS. 20 and 21 show a permanent bar magnet 219 disposed on theproximal end of the driver coil pack 188. As shown in FIG. 21, the barmagnet 219 is arranged so as to have one end disposed adjacent thetravel path of the magnetic member 202 and has a polarity configured soas to attract the magnetic member 202 in a centered position withrespect to the bar magnet 219. Note that the polymer guide tube 205′ canbe configured to extend proximally to insulate the inward radial surfaceof the bar magnet 219 from an outer surface of the magnetic member 202.This arrangement allows the magnetic member 219 and thus the elongatecoupler shaft 184 to be attracted to and held in a zero point or restposition without the consumption of electrical energy from the powersupply 225.

[0174] Having a fixed zero or start point for the elongate coupler shaft184 and lancet 183 can be critical to properly controlling the depth ofpenetration of the lancet 183 as well as other lancing parameters. Thiscan be because some methods of depth penetration control for acontrollable driver measure the acceleration and displacement of theelongate coupler shaft 184 and lancet 183 from a known start position.If the distance of the lancet tip 196 from the target tissue is known,acceleration and displacement of the lancet is known and the startposition of the lancet is know, the time and position of tissue contactand depth of penetration can be determined by the processor 193.

[0175] Any number of configurations for a magnetic bar 219 can be usedfor the purposes discussed above. In particular, a second permanent barmagnet (not shown) could be added to the proximal end of the driver coilpack 188 with the magnetic fields of the two bar magnets configured tocomplement each other. In addition, a disc magnet 219′ could be used asillustrated in FIG. 22. Disc magnet 219′ is shown disposed at theproximal end of the driver coiled pack 188 with a polymer non-magneticdisc 219″ disposed between the proximal-most coil 217 and disc magnet219′ and positions disc magnet 219′ away from the proximal end of theproximal-most coil 217. The polymer non-magnetic disc spacer 219″ isused so that the magnetic member 202 can be centered in a zero or startposition slightly proximal of the proximal-most coil 217 of the drivercoil pack 188. This allows the magnetic member to be attracted by theproximal-most coil 217 at the initiation of the lancing cycle instead ofbeing passive in the forward drive portion of the lancing cycle.

[0176] An inner lumen of the polymer non-magnetic disc 219″ can beconfigured to allow the magnetic member 202 to pass axially therethrough while an inner lumen of the disc magnet 219′ can be configuredto allow the elongate coupler shaft 184 to pass through but not largeenough for the magnetic member 202 to pass through. This results in themagnetic member 202 being attracted to the disc magnet 219′ and comingto rest with the proximal surface of the magnetic member 202 against adistal surface of the disc magnet 219′. This arrangement provides for apositive and repeatable stop for the magnetic member, and hence thelancet. A similar configuration could also be used for the bar magnet219 discussed above.

[0177] Typically, when the electrical current in the coils 214-217 ofthe driver coil pack 188 is off, a magnetic member 202 made of soft ironis attracted to the bar magnet 219 or disc magnet 219′. The magneticfield of the driver coil pack 188 and the bar magnet 219 or disc magnet219′, or any other suitable magnet, can be configured such that when theelectrical current in the coils 214-217 is turned on, the leakagemagnetic field from the coils 214-217 has the same polarity as the barmagnet 219 or disc magnet 219′. This results in a magnetic force thatrepels the magnetic member 202 from the bar magnet 219 or disc magnet219′ and attracts the magnetic member 202 to the activated coils214-217. For this configuration, the bar magnet 219 or disc magnet thusact to facilitate acceleration of the magnetic member 202 as opposed toworking against the acceleration.

[0178] Electrical conductors 222 couple the driver coil pack 188 withthe processor 193 which can be configured or programmed to control thecurrent flow in the coils 214-217 of the driver coil pack 188 based onposition feedback from the position sensor 191, which is coupled to theprocessor 193 by electrical conductors 194. A power source 225 iselectrically coupled to the processor 193 and provides electrical powerto operate the processor 193 and power the coil driver pack 188. Thepower source 225 may be one or more batteries that provide directcurrent power to the 193 processor.

[0179]FIG. 23 shows a transverse cross sectional view of drive coupler185 in more detail. The drive head 198 of the lancet 183 is disposedwithin the drive coupler 185 with a first retaining rail 226 and secondretaining rail 227 capturing the drive head 198 while allowing the drivehead 198 to be inserted laterally into the drive coupler 185 andretracted laterally with minimal mechanical resistance. The drivecoupler 185 may optionally be configured to include snap ridges 228which allow the drive head 198 to be laterally inserted and retracted,but keep the drive head 198 from falling out of the drive coupler 185unless a predetermined amount of externally applied lateral force isapplied to the drive head 198 of the lancet 183 towards the lateralopening 231 of the drive coupler 185. FIG. 27 shows an enlarged sideview into the coupler opening 231 of the drive coupler 185 showing thesnap ridges 228 disposed in the lateral opening 231 and the retainingrails 226 and 227. FIG. 28 shows an enlarged front view of the drivecoupler 185. The drive coupler 185 can be made from an alloy such asstainless steel, titanium or aluminum, but may also be made from asuitable polymer such as ABS, PVC, polycarbonate plastic or the like.The drive coupler may be open on both sides allowing the drive head andlancet to pass through.

[0180] Referring to FIG. 24, the magnetic member 202 is disposed aboutand secured to the elongate coupler shaft 184. The magnetic member 202is disposed within the axial lumen 232 of the fourth coil 217. Thedriver coil pack 188 is secured to the base 213. In FIG. 25 the positionsensor 191 is secured to the base 213 with the first body portion 208 ofthe position sensor 191 disposed opposite the second body portion 209 ofthe position sensor 191 with the first and second body portions 208 and209 of the position sensor 191 separated by the gap or slot 207. Theelongate coupler shaft 184 is slidably disposed within the gap 207between the first and second body portions 208 and 209 of the positionsensor 191. The optical encoder flag 206 is secured to the elongatecoupler shaft 184 and disposed between the first body portion 208 andsecond body portion 209 of the position sensor 191. Referring to FIG.26, the proximal portion 192 of the elongate coupler shaft 184 isdisposed within the guide lumen 212 of the coupler shaft guide 211. Theguide lumen 212 of the coupler shaft guide 211 may be lined with a lowfriction material such as Teflon® or the like to reduce friction of theelongate coupler shaft 184 during the power stroke of the lancing device180.

[0181] Referring to FIGS. 29A-29C, a flow diagram is shown thatdescribes the operations performed by the processor 193 in controllingthe lancet 183 of the lancing device 180 discussed above during anoperating cycle. FIGS. 30-36 illustrate the interaction of the lancet183 and skin 233 of the patient's finger 234 during an operation cycleof the lancet device 183. The processor 193 operates under control ofprogramming steps that are stored in an associated memory. When theprogramming steps are executed, the processor 193 performs operations asdescribed herein. Thus, the programming steps implement thefunctionality of the operations described with respect to the flowdiagram of FIG. 29. The processor 193 can receive the programming stepsfrom a program product stored in recordable media, including a directaccess program product storage device such as a hard drive or flash ROM,a removable program product storage device such as a floppy disk, or inany other manner known to those of skill in the art. The processor 193can also download the programming steps through a network connection orserial connection.

[0182] In the first operation, represented by the flow diagram boxnumbered 245 in FIG. 29A, the processor 193 initializes values that itstores in memory relating to control of the lancet, such as variablesthat it uses to keep track of the controllable driver 179 duringmovement. For example, the processor may set a clock value to zero and alancet position value to zero or to some other initial value. Theprocessor 193 may also cause power to be removed from the coil pack 188for a period of time, such as for about 10 ms, to allow any residualflux to dissipate from the coils.

[0183] In the initialization operation, the processor 193 also causesthe lancet to assume an initial stationary position. When in the initialstationary position, the lancet 183 is typically fully retracted suchthat the magnetic member 202 is positioned substantially adjacent thefourth coil 217 of the driver coil pack 188, shown in FIG. 21 above. Theprocessor 193 can move the lancet 183 to the initial stationary positionby pulsing an electrical current to the fourth coil 217 to therebyattract the magnetic member 202 on the lancet 183 to the fourth coil217. Alternatively, the magnetic member can be positioned in the initialstationary position by virtue of a permanent magnet, such as bar magnet219, disc magnet 219′ or any other suitable magnet as discussed abovewith regard to the tissue penetration device illustrated in FIGS. 20 and21.

[0184] In the next operation, represented by the flow diagram boxnumbered 247, the processor 193 energizes one or more of the coils inthe coil pack 188. This should cause the lancet 183 to begin to move(i.e., achieve a non-zero speed) toward the skin target 233. Theprocessor 193 then determines whether or not the lancet is indeedmoving, as represented by the decision box numbered 249. The processor193 can determine whether the lancet 183 is moving by monitoring theposition of the lancet 183 to determine whether the position changesover time. The processor 193 can monitor the position of the lancet 183by keeping track of the position of the optical encoder flag 206 securedto the elongate coupler shaft 184 wherein the encoder 191 produces asignal coupled to the processor 193 that indicates the spatial positionof the lancet 183.

[0185] If the processor 193 determines (via timeout without motionevents) that the lancet 183 is not moving (a “No” result from thedecision box 249), then the process proceeds to the operationrepresented by the flow diagram box numbered 253, where the processordeems that an error condition is present. This means that some error inthe system is causing the lancet 183 not to move. The error may bemechanical, electrical, or software related. For example, the lancet 183may be stuck in the stationary position because something is impedingits movement.

[0186] If the processor 193 determines that the lancet 183 is indeedmoving (a “Yes” result from the decision box numbered 249), then theprocess proceeds to the operation represented by the flow diagram boxnumbered 257. In this operation, the processor 193 causes the lancet 183to continue to accelerate and launch toward the skin target 233, asindicated by the arrow 235 in FIG. 30. The processor 193 can achieveacceleration of the lancet 183 by sending an electrical current to anappropriate coil 214-217 such that the coil 214-217 exerts an attractivemagnetic launching force on the magnetic member 202 and causes themagnetic member 202 and the lancet 183 coupled thereto to move in adesired direction. For example, the processor 193 can cause anelectrical current to be sent to the third coil 216 so that the thirdcoil 216 attracts the magnetic member 202 and causes the magnetic member202 to move from a position adjacent the fourth coil 217 toward thethird coil 216. The processor preferably determines which coil 214-217should be used to attract the magnetic member 202 based on the positionof the magnetic member 202 relative to the coils 214-217. In thismanner, the processor 193 provides a controlled force to the lancet thatcontrols the movement of the lancet.

[0187] During this operation, the processor 193 periodically orcontinually monitors the position and/or velocity of the lancet 183. Inkeeping track of the velocity and position of the lancet 183 as thelancet 183 moves towards the patient's skin 233 or other tissue, theprocessor 193 also monitors and adjusts the electrical current to thecoils 214-217. In some embodiments, the processor 193 applies current toan appropriate coil 214-217 such that the lancet 183 continues to moveaccording to a desired direction and acceleration. In the instant case,the processor 193 applies current to the appropriate coil 214-217 thatwill cause the lancet 183 to continue to move in the direction of thepatient's skin 233 or other tissue to be penetrated.

[0188] The processor 193 may successively transition the current betweencoils 214-217 so that as the magnetic member 202 moves past a particularcoil 214-217, the processor 193 then shuts off current to that coil214-217 and then applies current to another coil 214-217 that willattract the magnetic member 202 and cause the magnetic member 202 tocontinue to move in the desired direction. In transitioning currentbetween the coils 214-217, the processor 193 can take into accountvarious factors, including the speed of the lancet 183, the position ofthe lancet 183 relative to the coils 214-217, the number of coils214-217, and the level of current to be applied to the coils 214-217 toachieve a desired speed or acceleration.

[0189] In the next operation, the processor 193 determines whether thecutting or distal end tip 196 of the lancet 183 has contacted thepatient's skin 233, as shown in FIG. 31 and as represented by thedecision box numbered 265 in FIG. 29B. The processor 193 may determinewhether the lancet 183 has made contact with the target tissue 233 by avariety of methods, including some that rely on parameters which aremeasured prior to initiation of a lancing cycle and other methods thatare adaptable to use during a lancing cycle without any predeterminedparameters.

[0190] In one embodiment, the processor 193 determines that the skin hasbeen contacted when the end tip 196 of the lancet 183 has moved apredetermined distance with respect to its initial position. If thedistance from the tip 961 of the lancet 183 to the target tissue 233 isknown prior to initiation of lancet 183 movement, the initial positionof the lancet 183 is fixed and known, and the movement and position ofthe lancet 183 can be accurately measured during a lancing cycle, thenthe position and time of lancet contact can be determined.

[0191] This method requires an accurate measurement of the distancebetween the lancet tip 196 and the patient's skin 233 when the lancet183 is in the zero time or initial position. This can be accomplished ina number of ways. One way is to control all of the mechanical parametersthat influence the distance from the lancet tip 196 to the patient'stissue or a surface of the lancing device 180 that will contact thepatient's skin 233. This could include the start position of themagnetic member 202, magnetic path tolerance, magnetic member 202dimensions, driver coil pack 188 location within the lancing device 180as a whole, length of the elongate coupling shaft 184, placement of themagnetic member 202 on the elongate coupling shaft 184, length of thelancet 183 etc.

[0192] If all these parameters, as well as others can be suitablycontrolled in manufacturing with a tolerance stack-up that isacceptable, then the distance from the lancet tip 196 to the targettissue 233 can be determined at the time of manufacture of the lancingdevice 180. The distance could then be programmed into the memory of theprocessor 193. If an adjustable feature is added to the lancing device180, such as an adjustable length elongate coupling shaft 184, this canaccommodate variations in all of the parameters noted above, exceptlength of the lancet 183. An electronic alternative to this mechanicalapproach would be to calibrate a stored memory contact point into thememory of the processor 193 during manufacture based on the mechanicalparameters described above.

[0193] In another embodiment, moving the lancet tip 196 to the targettissue 233 very slowly and gently touching the skin 233 prior toactuation can accomplish the distance from the lancet tip 196 to thetissue 233. The position sensor can accurately measure the distance fromthe initialization point to the point of contact, where the resistanceto advancement of the lancet 183 stops the lancet movement. The lancet183 is then retracted to the initialization point having measured thedistance to the target tissue 233 without creating any discomfort to theuser.

[0194] In another embodiment, the processor 193 may use software todetermine whether the lancet 183 has made contact with the patient'sskin 233 by measuring for a sudden reduction in velocity of the lancet183 due to friction or resistance imposed on the lancet 183 by thepatient's skin 233. The optical encoder 191 measures displacement of thelancet 183. The position output data provides input to the interruptinput of the processor 193. The processor 193 also has a timer capableof measuring the time between interrupts. The distance betweeninterrupts is known for the optical encoder 191, so the velocity of thelancet 183 can be calculated by dividing the distance between interruptsby the time between the interrupts.

[0195] This method requires that velocity losses to the lancet 183 andelongate coupler 184 assembly due to friction are known to an acceptablelevel so that these velocity losses and resulting deceleration can beaccounted for when establishing a deceleration threshold above whichcontact between lancet tip 196 and target tissue 233 will be presumed.This same concept can be implemented in many ways. For example, ratherthan monitoring the velocity of the lancet 183, if the processor 193 iscontrolling the lancet driver in order to maintain a fixed velocity, thepower to the driver 188 could be monitored. If an amount of power abovea predetermined threshold is required in order to maintain a constantvelocity, then contact between the tip of the lancet 196 and the skin233 could be presumed.

[0196] In yet another embodiment, the processor 193 determines skin 233contact by the lancet 183 by detection of an acoustic signal produced bythe tip 196 of the lancet 183 as it strikes the patient's skin 233.Detection of the acoustic signal can be measured by an acoustic detector236 placed in contact with the patient's skin 233 adjacent a lancetpenetration site 237, as shown in FIG. 31. Suitable acoustic detectors236 include piezo electric transducers, microphones and the like. Theacoustic detector 236 transmits an electrical signal generated by theacoustic signal to the processor 193 via electrical conductors 238. Inanother embodiment, contact of the lancet 183 with the patient's skin233 can be determined by measurement of electrical continuity in acircuit that includes the lancet 183, the patient's finger 234 and anelectrical contact pad 240 that is disposed on the patient's skin 233adjacent the contact site 237 of the lancet 183, as shown in FIG. 31. Inthis embodiment, as soon as the lancet 183 contacts the patient's skin233, the circuit 239 is completed and current flows through the circuit239. Completion of the circuit 239 can then be detected by the processor193 to confirm skin 233 contact by the lancet 183.

[0197] If the lancet 183 has not contacted the target skin 233, then theprocess proceeds to a timeout operation, as represented by the decisionbox numbered 267 in FIG. 29B. In the timeout operation, the processor193 waits a predetermined time period. If the timeout period has not yetelapsed (a “No” outcome from the decision box 267), then the processorcontinues to monitor whether the lancet has contacted the target skin233. The processor 193 preferably continues to monitor the position andspeed of the lancet 183, as well as the electrical current to theappropriate coil 214-217 to maintain the desired lancet 183 movement.

[0198] If the timeout period elapses without the lancet 183 contactingthe skin (a “Yes” output from the decision box 267), then it is deemedthat the lancet 183 will not contact the skin and the process proceedsto a withdraw phase, where the lancet is withdrawn away from the skin233, as discussed more fully below. The lancet 183 may not havecontacted the target skin 233 for a variety of reasons, such as if thepatient removed the skin 233 from the lancing device or if somethingobstructed the lancet 183 prior to it contacting the skin.

[0199] The processor 193 may also proceed to the withdraw phase prior toskin contact for other reasons. For example, at some point afterinitiation of movement of the lancet 183, the processor 193 maydetermine that the forward acceleration of the lancet 183 towards thepatient's skin 233 should be stopped or that current to all coils214-217 should be shut down. This can occur, for example, if it isdetermined that the lancet 183 has achieved sufficient forward velocity,but has not yet contacted the skin 233. In one embodiment, the averagepenetration velocity of the lancet 183 from the point of contact withthe skin to the point of maximum penetration may be about 2.0 to about10.0 m/s, specifically, about 3.8 to about 4.2 m/s. In anotherembodiment, the average penetration velocity of the lancet may be fromabout2 to about 8 meters per second, specifically, about2 to about 4m/s.

[0200] The processor 193 can also proceed to the withdraw phase if it isdetermined that the lancet 183 has fully extended to the end of thepower stroke of the operation cycle of lancing procedure. In otherwords, the process may proceed to withdraw phase when an axial center241 of the magnetic member 202 has moved distal of an axial center 242of the first coil 214 as show in FIG. 21. In this situation, anycontinued power to any of the coils 214-217 of the driver coil pack 188serves to decelerate the magnetic member 202 and thus the lancet 183. Inthis regard, the processor 193 considers the length of the lancet 183(which can be stored in memory) the position of the lancet 183 relativeto the magnetic member 202, as well as the distance that the lancet 183has traveled.

[0201] With reference again to the decision box 265 in FIG. 29B, if theprocessor 193 determines that the lancet 183 has contacted the skin 233(a “Yes” outcome from the decision box 265), then the processor 193 canadjust the speed of the lancet 183 or the power delivered to the lancet183 for skin penetration to overcome any frictional forces on the lancet183 in order to maintain a desired penetration velocity of the lancet.The flow diagram box numbered 267 represents this.

[0202] As the velocity of the lancet 183 is maintained after contactwith the skin 233, the distal tip 196 of the lancet 183 will first beginto depress or tent the contacted skin 237 and the skin 233 adjacent thelancet 183 to form a tented portion 243 as shown in FIG. 32 and furthershown in FIG. 33. As the lancet 183 continues to move in a distaldirection or be driven in a distal direction against the patient's skin233, the lancet 183 will eventually begin to penetrate the skin 233, asshown in FIG. 34. Once penetration of the skin 233 begins, the staticforce at the distal tip 196 of the lancet 183 from the skin 233 willbecome a dynamic cutting force, which is generally less than the statictip force. As a result in the reduction of force on the distal tip 196of the lancet 183 upon initiation of cutting, the tented portion 243 ofthe skin 233 adjacent the distal tip 196 of the lancet 183 which hadbeen depressed as shown in FIGS. 32 and 24 will spring back as shown inFIG. 34.

[0203] In the next operation, represented by the decision box numbered271 in FIG. 29B, the processor 193 determines whether the distal end 196of the lancet 183 has reached a brake depth. The brake depth is the skinpenetration depth for which the processor 193 determines thatdeceleration of the lancet 183 is to be initiated in order to achieve adesired final penetration depth 244 of the lancet 183 as show in FIG.35. The brake depth may be pre-determined and programmed into theprocessor's memory, or the processor 193 may dynamically determine thebrake depth during the actuation. The amount of penetration of thelancet 183 in the skin 233 of the patient may be measured during theoperation cycle of the lancet device 180. In addition, as discussedabove, the penetration depth necessary for successfully obtaining auseable sample can depend on the amount of tenting of the skin 233during the lancing cycle. The amount of tenting of the patient's skin233 can in turn depend on the tissue characteristics of the patient suchas elasticity, hydration etc. A method for determining thesecharacteristics is discussed below with regard to skin 233 tentingmeasurements during the lancing cycle and illustrated in FIGS. 37-41.

[0204] Penetration measurement can be carried out by a variety ofmethods that are not dependent on measurement of tenting of thepatient's skin. In one embodiment, the penetration depth of the lancet183 in the patient's skin 233 is measured by monitoring the amount ofcapacitance between the lancet 183 and the patient's skin 233. In thisembodiment, a circuit includes the lancet 183, the patient's finger 234,the processor 193 and electrical conductors connecting these elements.As the lancet 183 penetrates the patient's skin 233, the greater theamount of penetration, the greater the surface contact area between thelancet 183 and the patient's skin 233. As the contact area increases, sodoes the capacitance between the skin 233 and the lancet 183. Theincreased capacitance can be easily measured by the processor 193 usingmethods known in the art and penetration depth can then be correlated tothe amount of capacitance. The same method can be used by measuring theelectrical resistance between the lancet 183 and the patient's skin.

[0205] If the brake depth has not yet been reached, then a “No” resultsfrom the decision box 271 and the process proceeds to the timeoutoperation represented by the flow diagram box numbered 273. In thetimeout operation, the processor 193 waits a predetermined time period.If the timeout period has not yet elapsed (a “No” outcome from thedecision box 273), then the processor continues to monitor whether thebrake depth has been reached. If the timeout period elapses without thelancet 183 achieving the brake depth (a “Yes” output from the decisionbox 273), then the processor 193 deems that the lancet 183 will notreach the brake depth and the process proceeds to the withdraw phase,which is discussed more fully below. This may occur, for example, if thelancet 183 is stuck at a certain depth.

[0206] With reference again to the decision box numbered 271 in FIG.29B, if the lancet does reach the brake depth (a “Yes” result), then theprocess proceeds to the operation represented by the flow diagram boxnumbered 275. In this operation, the processor 193 causes a brakingforce to be applied to the lancet to thereby reduce the speed of thelancet 183 to achieve a desired amount of final skin penetration depth244, as shown in FIG. 26. Note that FIGS. 32 and 33 illustrate thelancet making contact with the patient's skin and deforming ordepressing the skin prior to any substantial penetration of the skin.The speed of the lancet 183 is preferably reduced to a value below adesired threshold and is ultimately reduced to zero. The processor 193can reduce the speed of the lancet 183 by causing a current to be sentto a 214-217 coil that will exert an attractive braking force on themagnetic member 202 in a proximal direction away from the patient'stissue or skin 233, as indicated by the arrow 290 in FIG. 36. Such anegative force reduces the forward or distally oriented speed of thelancet 183. The processor 193 can determine which coil 214-217 toenergize based upon the position of the magnetic member 202 with respectto the coils 214-217 of the driver coil pack 188, as indicated by theposition sensor 191.

[0207] In the next operation, the process proceeds to the withdrawphase, as represented by the flow diagram box numbered 277. The withdrawphase begins with the operation represented by the flow diagram boxnumbered 279 in FIG. 29C. Here, the processor 193 allows the lancet 183to settle at a position of maximum skin penetration 244, as shown inFIG. 35. In this regard, the processor 193 waits until any motion in thelancet 183 (due to vibration from impact and spring energy stored in theskin, etc.) has stopped by monitoring changes in position of the lancet183. The processor 193 preferably waits until several milliseconds (ms),such as on the order of about 8 ms, have passed with no changes inposition of the lancet 183. This is an indication that movement of thelancet 183 has ceased entirely. In some embodiments, the lancet may beallowed to settle for about 1 to about 2000 milliseconds, specifically,about 50 to about 200 milliseconds. For other embodiments, the settlingtime may be about 1 to about 200 milliseconds.

[0208] It is at this stage of the lancing cycle that a software methodcan be used to measure the amount of tenting of the patient's skin 233and thus determine the skin 233 characteristics such as elasticity,hydration and others. Referring to FIGS. 37-41, a lancet 183 isillustrated in various phases of a lancing cycle with target tissue 233.FIG. 37 shows tip 196 of lancet 183 making initial contact with the skin233 at the point of initial impact.

[0209]FIG. 38 illustrates an enlarged view of the lancet 183 makinginitial contact with the tissue 233 shown in FIG. 37. In FIG. 39, thelancet tip 196 has depressed or tented the skin 233 prior to penetrationover a distance of X, as indicated by the arrow labeled X in FIG. 39. InFIG. 40, the lancet 183 has reached the full length of the cutting powerstroke and is at maximum displacement. In this position, the lancet tip196 has penetrated the tissue 233 a distance of Y, as indicated by thearrow labeled Y in FIG. 39. As can be seen from comparing FIG. 38 withFIG. 40, the lancet tip 196 was displaced a total distance of X plus Yfrom the time initial contact with the skin 233 was made to the time thelancet tip 196 reached its maximum extension as shown in FIG. 40.However, the lancet tip 196 has only penetrated the skin 233 a distanceY because of the tenting phenomenon.

[0210] At the end of the power stroke of the lancet 183, as discussedabove with regard to FIG. 26 and box 279 of FIG. 29C, the processor 193allows the lancet to settle for about 8 msec. It is during this settlingtime that the skin 233 rebounds or relaxes back to approximately itsoriginal configuration prior to contact by the lancet 183 as shown inFIG. 41. The lancet tip 196 is still buried in the skin to a depth of Y,as shown in FIG. 41, however the elastic recoil of the tissue hasdisplaced the lancet rearward or retrograde to the point of inelastictenting that is indicated by the arrows Z in FIG. 41. During therearward displacement of the lancet 183 due to the elastic tenting ofthe tissue 233, the processor reads and stores the position datagenerated by the position sensor 191 and thus measures the amount ofelastic tenting, which is the difference between X and Z.

[0211] The tenting process and retrograde motion of the lancet 183during the lancing cycle is illustrated graphically in FIG. 42 whichshows both a velocity versus time graph and a position versus time graphof a lancet tip 196 during a lancing cycle that includes elastic andinelastic tenting. In FIG. 42, from point 0 to point A, the lancet 183is being accelerated from the initialization position or zero position.From point A to point B, the lancet is in ballistic or coasting mode,with no additional power being delivered. At point B, the lancet tip 196contacts the tissue 233 and begins to tent the skin 233 until it reachesa displacement C. As the lancet tip 196 approaches maximum displacement,braking force is applied to the lancet 183 until the lancet comes to astop at point D. The lancet 183 then recoils in a retrograde directionduring the settling phase of the lancing cycle indicated between D andE. Note that the magnitude of inelastic tenting indicated in FIG. 42 isexaggerated for purposes of illustration.

[0212] The amount of inelastic tenting indicated by Z tends to be fairlyconsistent and small compared to the magnitude of the elastic tenting.Generally, the amount of inelastic tenting Z can be about 120 to about140 microns. As the magnitude of the inelastic tenting has a fairlyconstant value and is small compared to the magnitude of the elastictenting for most patients and skin types, the value for the total amountof tenting for the penetration stroke of the lancet 183 is effectivelyequal to the rearward displacement of the lancet during the settlingphase as measured by the processor 193 plus a predetermined value forthe inelastic recoil, such as 130 microns. Inelastic recoil for someembodiments can be about 100 to about 200 microns. The ability tomeasure the magnitude of skin 233 tenting for a patient is important tocontrolling the depth of penetration of the lancet tip 196 as the skinis generally known to vary in elasticity and other parameters due toage, time of day, level of hydration, gender and pathological state.

[0213] This value for total tenting for the lancing cycle can then beused to determine the various characteristics of the patient's skin 233.Once a body of tenting data is obtained for a given patient, this datacan be analyzed in order to predict the total lancet displacement, fromthe point of skin contact, necessary for a successful lancing procedure.This enables the tissue penetration device to achieve a high successrate and minimize pain for the user. A rolling average table can be usedto collect and store the tenting data for a patient with a pointer tothe last entry in the table. When a new entry is input, it can replacethe entry at the pointer and the pointer advances to the next value.When an average is desired, all the values are added and the sum dividedby the total number of entries by the processor 193. Similar techniquesinvolving exponential decay (multiply by 0.95, add 0.05 times currentvalue, etc.) are also possible.

[0214] With regard to tenting of skin 233 generally, some typical valuesrelating to penetration depth are now discussed. FIG. 43 shows a crosssectional view of the layers of the skin 233. In order to reliablyobtain a useable sample of blood from the skin 233, it is desirable tohave the lancet tip 196 reach the venuolar plexus of the skin. Thestratum corneum is typically about 0.1 to about 0.6 mm thick and thedistance from the top of the dermis to the venuole plexus can be fromabout 0.3 to about 1.4 mm. Elastic tenting can have a magnitude of up toabout2 mm or so, specifically, about 0.2 to about 2.0 mm, with anaverage magnitude of about 1 mm. This means that the amount of lancetdisplacement necessary to overcome the tenting can have a magnitudegreater than the thickness of skin necessary to penetrate in order toreach the venuolar plexus. The total lancet displacement from point ofinitial skin contact may have an average value of about 1.7 to about 2.1mm. In some embodiments, penetration depth and maximum penetration depthmay be about 0.5 mm to about5 mm, specifically, about 1 mm to about 3mm. In some embodiments, a maximum penetration depth of about 0.5 toabout 3 mm is useful.

[0215] Referring back to FIG. 29C, in the next operation, represented bythe flow diagram box numbered 280 in FIG. 29C, the processor 193 causesa withdraw force to be exerted on the lancet 183 to retract the lancet183 from the skin 233, as shown by arrow 290 in FIG. 36 The processor193 sends a current to an appropriate coil 214-217 so that the coil214-217 exerts an attractive distally oriented force on the magneticmember 202, which should cause the lancet 183 to move backward in thedesired direction. In some embodiments, the lancet 183 is withdrawn withless force and a lower speed than the force and speed during thepenetration portion of the operation cycle. Withdrawal speed of thelancet in some embodiments can be about 0.004 to about 0.5 m/s,specifically, about 0.006 to about 0.01 m/s. In other embodiments,useful withdrawal velocities can be about 0.001 to about 0.02 meters persecond, specifically, about 0.001 to about 0.01 meters per second. Forembodiments that use a relatively slow withdrawal velocity compared tothe penetration velocity, the withdrawal velocity may up to about 0.02meters per second. For such embodiments, a ratio of the averagepenetration velocity relative to the average withdrawal velocity can beabout 100 to about 1000. In embodiments where a relatively slowwithdrawal velocity is not important, a withdrawal velocity of about 2to about 10 meters per second may be used.

[0216] In the next operation, the processor 193 determines whether thelancet 183 is moving in the desired backward direction as a result ofthe force applied, as represented by the decision box numbered 281. Ifthe processor 193 determines that the lancet 183 is not moving (a “No”result from the decision box 281), then the processor 193 continues tocause a force to be exerted on the lancet 183, as represented by theflow diagram box numbered 282. The processor 193 may cause a strongerforce to be exerted on the lancet 183 or may just continue to apply thesame amount of force. The processor then again determines whether thelancet is moving, as represented by the decision box numbered 283. Ifmovement is still not detected (a “No” result from the decision boxnumbered 283), the processor 193 determines that an error condition ispresent, as represented by the flow diagram box numbered 284. In such asituation, the processor preferably de-energizes the coils to removeforce from the lancet, as the lack of movement may be an indication thatthe lancet is stuck in the skin of the patient and, therefore, that itmay be undesirable to continue to attempt pull the lancet out of theskin.

[0217] With reference again to the decision boxes numbered 281 and 283in FIG. 29C, if the processor 193 determines that the lancet is indeedmoving in the desired backward direction away from the skin 233, thenthe process proceeds to the operation represented by the flow diagrambox numbered 285. In this operation, the backward movement of the lancet183 continues until the lancet distal end has been completely withdrawnfrom the patient's skin 233. As discussed above, in some embodiments thelancet 183 is withdrawn with less force and a lower speed than the forceand speed during the penetration portion of the operation cycle. Therelatively slow withdrawal of the lancet 183 may allow the blood fromthe capillaries of the patient accessed by the lancet 183 to follow thelancet 183 during withdrawal and reach the skin surface to reliablyproduce a usable blood sample. The process then ends.

[0218] Controlling the lancet motion over the operating cycle of thelancet 183 as discussed above allows a wide variety of lancet velocityprofiles to be generated by the lancing device 180. In particular, anyof the lancet velocity profiles discussed above with regard to otherembodiments can be achieved with the processor 193, position sensor 191and driver coil pack 188 of the lancing device 180.

[0219] Another example of an embodiment of a velocity profile for alancet can be seen in FIGS. 44 and 45, which illustrates a lancetprofile with a fast entry velocity and a slow withdrawal velocity. FIG.44 illustrates an embodiment of a lancing profile showing velocity ofthe lancet versus position. The lancing profile starts at zero time andposition and shows acceleration of the lancet towards the tissue fromthe electromagnetic force generated from the electromagnetic driver. Atpoint A, the power is shut off and the lancet 183 begins to coast untilit reaches the skin 233 indicated by B at which point, the velocitybegins to decrease. At point C, the lancet 183 has reached maximumdisplacement and settles momentarily, typically for a time of about 8milliseconds.

[0220] A retrograde withdrawal force is then imposed on the lancet bythe controllable driver, which is controlled by the processor tomaintain a withdrawal velocity of no more than about 0.006 to about 0.01meters/second. The same cycle is illustrated in the velocity versus timeplot of FIG. 45 where the lancet is accelerated from the start point topoint A. The lancet 183 coasts from A to B where the lancet tip 196contacts tissue 233. The lancet tip 196 then penetrates the tissue andslows with braking force eventually applied as the maximum penetrationdepth is approached. The lancet is stopped and settling between C and D.At D, the withdrawal phase begins and the lancet 183 is slowly withdrawnuntil it returns to the initialization point shown by E in FIG. 45. Notethat retrograde recoil from elastic and inelastic tenting was not shownin the lancing profiles of FIGS. 44 and 45 for purpose of illustrationand clarity.

[0221] In another embodiment, the withdrawal phase may use a dual speedprofile, with the slow 0.006 to 0.01 meter per second speed used untilthe lancet is withdrawn past the contact point with the tissue, then afaster speed of 0.01 to 1 meters per second may be used to shorten thecomplete cycle.

[0222] Referring to FIG. 46, another embodiment of a lancing deviceincluding a controllable driver 294 with a driver coil pack 295,position sensor and lancet 183 are shown. The lancet 297 has a proximalend 298 and a distal end 299 with a sharpened point at the distal end299 of the lancet 297. A magnetic member 301 disposed about and securedto a proximal end portion 302 of the lancet 297 with a lancet shaft 303being disposed between the magnetic member 301 and the sharpened point299. The lancet shaft 303 may be comprised of stainless steel, or anyother suitable material or alloy. The lancet shaft 303 may have a lengthof about 3 mm to about 50 mm specifically, about 5 mm to about 15 mm.

[0223] The magnetic member 301 is configured to slide within an axiallumen 304 of the driver coil pack 295. The driver coil pack 295 includesa most distal first coil 305, a second coil 306, which is axiallydisposed between the first coil 305 and a third coil 307, and aproximal-most fourth coil 308. Each of the first coil 305, second coil306, third coil 307 and fourth coil 308 has an axial lumen. The axiallumens of the first through fourth coils 305-308 are configured to becoaxial with the axial lumens of the other coils and together form theaxial lumen 309 of the driver coil pack 295 as a whole. Axially adjacenteach of the coils 305-308 is a magnetic disk or washer 310 that augmentscompletion of the magnetic circuit of the coils 305-308 during a lancingcycle of the driven coil pack 295. The magnetic washers 310 of theembodiment of FIG. 46 are made of ferrous steel but could be made of anyother suitable magnetic material, such as iron or ferrite. The magneticwashers 310 have an outer diameter commensurate with an outer diameterof the driver coil pack 295 of about 4.0 to about 8.0 mm. The magneticwashers 310 have an axial thickness of about 0.05, to about 0.4 mm,specifically, about 0.15 to about 0.25 mm. The outer shell 294 of thecoil pack is also made of iron or steel to complete the magnetic patharound the coils and between the washers 310.

[0224] Wrapping or winding an elongate electrical conductor 311 aboutthe axial lumen 309 until a sufficient number of windings have beenachieved forms the coils 305-308. The elongate electrical conductor 311is generally an insulated solid copper wire. The particular materials,dimensions number of coil windings etc. of the coils 305-308, washers310 and other components of the driver coil pack 295 can be the same orsimilar to the materials, dimensions number of coil windings etc. of thedriver coil pack 188 discussed above.

[0225] Electrical conductors 312 couple the driver coil pack 295 with aprocessor 313 which can be configured or programmed to control thecurrent flow in the coils 305-308 of the driver coil pack 295 based onposition feedback from the position sensor 296, which is coupled to theprocessor 313 by electrical conductors 315. A power source 316 iselectrically coupled to the processor 313 and provides electrical powerto operate the processor 313 and power the driver coil pack 295. Thepower source 316 may be one or more batteries (not shown) that providedirect current power to the processor 313 as discussed above.

[0226] The position sensor 296 is an analog reflecting light sensor thathas a light source and light receiver in the form of a photo transducer317 disposed within a housing 318 with the housing 318 secured in fixedspatial relation to the driver coil pack 295. A reflective member 319 isdisposed on or secured to a proximal end 320 of the magnetic member 301.The processor 313 determines the position of the lancet 299 by firstemitting light from the light source of the photo transducer 317 towardsthe reflective member 319 with a predetermined solid angle of emission.Then, the light receiver of the photo transducer 317 measures theintensity of light reflected from the reflective member 319 andelectrical conductors 315 transmit the signal generated therefrom to theprocessor 313.

[0227] By calibrating the intensity of reflected light from thereflective member 319 for various positions of the lancet 297 during theoperating cycle of the driver coil pack 295, the position of the lancet297 can thereafter be determined by measuring the intensity of reflectedlight at any given moment. In one embodiment, the sensor 296 uses acommercially available LED/photo transducer module such as the OPB703manufactured by Optek Technology, Inc., 1215 W. Crosby Road, Carrollton,Tex., 75006. This method of analog reflective measurement for positionsensing can be used for any of the embodiments of lancet actuatorsdiscussed herein. In addition, any of the lancet actuators or driversthat include coils may use one or more of the coils to determine theposition of the lancet 297 by using a magnetically permeable region onthe lancet shaft 303 or magnetic member 301 itself as the core of aLinear Variable Differential Transformer (LVDT).

[0228] Referring to FIGS. 47 and 48, a flat coil lancet driver 325 isillustrated which has a main body housing 326 and a rotating frame 327.The rotating frame 327 pivots about an axle 328 disposed between a base329, a top body portion 330 of the main body housing 326 and disposed ina pivot guide 331 of the rotating frame 327. An actuator arm 332 of therotating frame 327 extends radially from the pivot guide 331 and has alinkage receiving opening 333 disposed at an outward end 334 of theactuator arm 332. A first end 335 of a coupler linkage 336 is coupled tothe linkage receiving opening 333 of the actuator arm 332 and can rotatewithin the linkage receiving opening 333. A second end 337 of thecoupler linkage 336 is disposed within an opening at a proximal end 338of a coupler translation member 341. This configuration allowscircumferential forces imposed upon the actuator arm 332 to betransferred into linear forces on a drive coupler 342 secured to adistal end 343 of the coupler translation member 341. The materials anddimensions of the drive coupler 342 can be the same or similar to thematerials and dimensions of the drive coupler 342 discussed above.

[0229] Opposite the actuator arm 332 of the rotating frame 327, atranslation substrate in the form of a coil arm 344 extends radiallyfrom the pivot guide 331 of the rotating frame 327. The coil arm 344 issubstantially triangular in shape. A flat coil 345 is disposed on andsecured to the coil arm 344. The flat coil 345 has leading segment 346and a trailing segment 347, both of which extend substantiallyorthogonal to the direction of motion of the segments 346 and 347 whenthe rotating frame 327 is rotating about the pivot guide 331. Theleading segment 346 is disposed within a first magnetically activeregion 348 generated by a first upper permanent magnet 349 secured to anupper magnet base 351 and a first lower permanent magnet 352 secured toa lower magnet base 353. The trailing segment 347 is disposed within asecond magnetically active region 354 generated by a second upperpermanent magnet 355 secured to the upper magnet base 351 and a secondlower permanent magnet secured to the lower magnet base 353.

[0230] The magnetic field lines or circuit of the first upper and lowerpermanent magnets 349, 352, 355 and 356 can be directed upward from thefirst lower permanent magnet 352 to the first upper permanent magnet 349or downward in an opposite direction. The magnetic field lines from thesecond permanent magnets 355 and 356 are also directed up or down, andwill have a direction opposite to that of the first upper and lowerpermanent magnets 349 and 352. This configuration produces rotationalforce on the coil arm 344 about the pivot guide 331 with the directionof the force determined by the direction of current flow in the flatcoil 345. As seen in FIGS. 47 and 48, the movable member 327 is notfully enclosed, encircled, or surrounded by the magnets 349, 353, 355,and 356. It should be understood that in other embodiments, theconfiguration may be altered such that the movable member 327 contains amagnet and coils take the place of items 349, 353, 355, and 356 in thosepositions. Thus, the coil is a flat coil that does not fully enclose themovable member.

[0231] A position sensor 357 includes an optical encoder disk section358 is secured to the rotating frame 327 which rotates with the rotatingframe 327 and is read by an optical encoder 359 which is secured to thebase 329. The position sensor 357 determines the rotational position ofthe rotating frame 327 and sends the position information to a processor360 which can have features which are the same or similar to thefeatures of the processor 193 discussed above via electrical leads 361.Electrical conductor leads 363 of the flat coil 345 are alsoelectrically coupled to the processor 360.

[0232] As electrical current is passed through the leading segment 346and trailing segment 347 of the flat coil 345, the rotational forcesimposed on the segments 346 and 347 are transferred to the rotatingframe 327 to the actuator arm 332, through the coupler linkage 336 andcoupler translation member 341 and eventually to the drive coupler 342.In use, a lancet (not shown) is secured into the drive coupler 342, andthe flat coil lancet actuator 325 activated. The electrical current inthe flat coil 345 determines the forces generated on the drive coupler342, and hence, a lancet secured to the coupler 342. The processor 360controls the electrical current in the flat coil 345 based on theposition and velocity of the lancet as measured by the position sensor357 information sent to the processor 360. The processor 360 is able tocontrol the velocity of a lancet in a manner similar to the processor193 discussed above and can generate any of the desired lancet velocityprofiles discussed above, in addition to others.

[0233]FIGS. 49 and 50 depict yet another embodiment of a controlleddriver 369 having a driver coil pack 370 for a tissue penetrationdevice. The driver coil pack 370 has a proximal end 371, a distal end372 and an axial lumen 373 extending from the proximal end 371 to thedistal end 372. An inner coil 374 is disposed about the axial lumen 373and has a tapered configuration with increasing wraps per inch of anelongate conductor 375 in a distal direction. The inner coil 374 extendsfrom the proximal end 371 of the coil driver pack 370 to the distal end372 of the driver coil pack 370 with a major outer diameter ortransverse dimension of about 1 to about 25 mm, specifically about 1 toabout 12 mm.

[0234] The outer diameter or transverse dimension of the inner coil 374at the proximal end 371 of the driver coil pack 370 is approximatelyequal to the diameter of the axial lumen 373 at the proximal end 371 ofthe coil pack 370. That is, the inner coil 374 tapers to a reduce outerdiameter proximally until there are few or no wraps of elongateelectrical conductor 375 at the proximal end 371 of the driver coil pack370. The tapered configuration of the inner coil 374 produces an axialmagnetic field gradient within the axial lumen 373 of the driver coilpack 370 when the inner coil 374 is activated with electrical currentflowing through the elongate electrical conductor 375 of the inner coil374.

[0235] The axial magnetic field gradient produces a driving force for amagnetic member 376 disposed within the axial lumen 373 that drives themagnetic member 376 towards the distal end 372 of the driver coil pack370 when the inner coil 374 is activated. The driving force on themagnetic member produced by the inner coil 374 is a smooth continuousforce, which can produce a smooth and continuous acceleration of themagnetic member 376 and lancet 377 secured thereto. In some embodiments,the ratio of the increase in outer diameter versus axial displacementalong the inner coil 374 in a distal direction can be from about 1 toabout 0.08, specifically, about 1 to about 0.08.

[0236] An outer coil 378 is disposed on and longitudinally coextensivewith the inner coil 374. The outer coil 378 can have the same or similardimensions and construction as the inner coil 374, except that the outercoil 378 tapers proximally to an increased diameter or transversedimension. The greater wraps per inch of elongate electrical conductor379 in a proximal direction for the outer coil 378 produces a magneticfield gradient that drives the magnetic member 376 in a proximaldirection when the outer coil 378 is activated with electrical current.This produces a braking or reversing effect on the magnetic member 376during an operational cycle of the lancet 377 and driver coil pack 370.The elongate electrical conductors 375 and 379 of the inner coil 374 andouter coil 378 are coupled to a processor 381, which is coupled to anelectrical power source 382. The processor 381 can have propertiessimilar to the other processors discussed above and can control thevelocity profile of the magnetic member 376 and lancet 377 to produceany of the velocity profiles above as well as others. The driver coilpack 370 can be used as a substitute for the coil driver pack discussedabove, with other components of the lancing device 180 being the same orsimilar.

[0237] Embodiments of driver or actuator mechanisms having beendescribed, we now discuss embodiments of devices which can houselancets, collect samples of fluids, analyze the samples or anycombination of these functions. These front-end devices may beintegrated with actuators, such as those discussed above, or any othersuitable driver or controllable driver.

[0238] Generally, most known methods of blood sampling require severalsteps. First, a measurement session is set up by gathering variousarticles such as lancets, lancet drivers, test strips, analyzinginstrument, etc. Second, the patient must assemble the paraphernalia byloading a sterile lancet, loading a test strip, and arming the lancetdriver. Third, the patient must place a finger against the lancet driverand using the other hand to activate the driver. Fourth, the patientmust put down the lancet driver and place the bleeding finger against atest strip, (which may or may not have been loaded into an analyzinginstrument). The patient must insure blood has been loaded onto the teststrip and the analyzing instrument has been calibrated prior to suchloading. Finally, the patient must dispose of all the blood-contaminatedparaphernalia including the lancet. As such, integrating the lancing andsample collection features of a tissue penetration sampling device canachieve advantages with regard to patient convenience.

[0239]FIG. 51 shows a disposable sampling module 410, which houses thelancet 412. The lancet 412 has a head on a proximal end 416 whichconnects to the driver 438 and a distal end 414, which lances the skin.The distal end 414 is disposed within the conduit 418. The proximal end416 extends into the cavity 420. The sample reservoir 422 has a narrowinput port 424 on the ergonomically contoured surface 426, which isadjacent to the distal end 414 of the lancet 412. The term ergonomicallycontoured, as used herein, generally means shaped to snugly fit a fingeror other body portion to be lanced or otherwise tested placed on thesurface. The sampling module 410 is capable of transporting the bloodsample from the sample reservoir 422 through small passages (not shown),to an analytical region 428. The analytical region 428 can includechemical, physical, optical, electrical or other means of analyzing theblood sample. The lancet, sample flow channel, sample reservoir andanalytical region are integrated into the sampling module 410 in asingle packaged unit.

[0240]FIG. 52 shows the chamber 430 in the housing 410′ where thesampling module 410 is loaded. The sampling module 410 is loaded on asocket 432 suspended with springs 434 and sits in slot 436. A driver 438is attached to the socket 432. The driver 438 has a proximal end 440 anda distal end 442. The driver 438 can be either a controllable driver ornon-controllable driver any mechanical, such as spring or cam driven, orelectrical, such as electromagnetically or electronically driven, meansfor advancing, stopping, and retracting the lancet. There is a clearance444 between the distal end 442 of the driver 438 and the sensor 446,which is attached to the chamber 430. The socket 432 also contains ananalyzer 448, which is a system for analyzing blood. The analyzer 448corresponds to the analytical region 428 on the module 410 when it isloaded into the socket 432.

[0241]FIG. 53 shows a tissue penetration sampling device 411 with thesampling module 410 loaded into the socket 432 of housing 410′. Theanalytical region 428 and analyzer 448 overlap. The driver 438 fits intothe cavity 420. The proximal end 440 of the driver 438 abuts the distalend 416 of the lancet 412. The patient's finger 450 sits on theergonomically contoured surface 426.

[0242]FIG. 54 shows a drawing of an alternate lancet configuration wherethe lancet 412 and driver 438 are oriented to lance the side of thefinger 450 as it sits on the ergonomically contoured surface 426.

[0243]FIG. 55 illustrates the orifice 452 and ergonomically contouredsurface 426. The conduit 418 has an orifice 452, which opens on a bloodwell 454. The sample input port 424 of the reservoir 422 also opens onthe blood well 454. The diameter of the sample input port 424 issignificantly greater than the diameter of the orifice 452, which issubstantially the same diameter as the diameter of the lancet 412. Afterthe lancet is retracted, the blood flowing from the finger 450 willcollect in the blood well 454. The lancet 412 will have been retractedinto the orifice 452 effectively blocking the passage of blood down theorifice 452. The blood will flow from the blood well 454 through thesample input port 424 into the reservoir 422.

[0244]FIG. 56 shows a drawing of the lancing event. The patient appliespressure by pushing down with the finger 450 on the ergonomicallycontoured surface 426. This applies downward pressure on the samplingmodule 410, which is loaded into the socket 432. As the socket 432 ispushed downward it compresses the springs 434. The sensor 446 makescontact with the distal end 442 of the driver 438 and therebyelectrically detects the presence of the finger on the ergonomicallycontoured surface. The sensor can be a piezoelectric device, whichdetects this pressure and sends a signal to circuit 456, which actuatesthe driver 438 and advances and then retracts the lancet 412 lancing thefinger 450. In another embodiment, the sensor 446 is an electriccontact, which closes a circuit when it contacts the driver 438activating the driver 438 to advance and retract the lancet 412 lancingthe finger 450.

[0245] An embodiment of a method of sampling includes a reduced numberof steps that must be taken by a patient to obtain a sample and analysisof the sample. First, the patient loads a sampling module 410 with anembedded sterile lancet into the housing device 410′. Second, thepatient initiates a lancing cycle by turning on the power to the deviceor by placing the finger to be lanced on the ergonomically contouredsurface 426 and pressing down. Initiation of the sensor makes the sensoroperational and gives control to activate the launcher.

[0246] The sensor is unprompted when the lancet is retracted after itslancing cycle to avoid unintended multiple lancing events. The lancingcycle consists of arming, advancing, stopping and retracting the lancet,and collecting the blood sample in the reservoir. The cycle is completeonce the blood sample has been collected in the reservoir. Third, thepatient presses down on the sampling module, which forces the driver 38to make contact with the sensor, and activates the driver 438. Thelancet then pierces the skin and the reservoir collects the bloodsample.

[0247] The patient is then optionally informed to remove the finger byan audible signal such as a buzzer or a beeper, and/or a visual signalsuch as an LED or a display screen. The patient can then dispose of allthe contaminated parts by removing the sampling module 410 and disposingof it. In another embodiment, multiple sampling modules 410 may beloaded into the housing 410′ in the form of a cartridge (not shown). Thepatient can be informed by the tissue penetration sampling device 411 asto when to dispose of the entire cartridge after the analysis iscomplete.

[0248] In order to properly analyze a sample in the analytical region428 of the sampling module 410, it may be desirable or necessary todetermine whether a fluid sample is present in a given portion of thesample flow channel, sample reservoir or analytical area. A variety ofdevices and methods for determining the presence of a fluid in a regionare discussed below.

[0249] In FIG. 57, a thermal sensor 500 embedded in a substrate 502adjacent to a surface 504 over which a fluid may flow. The surface maybe, for example, a wall of a channel through which fluid may flow or asurface of a planar device over which fluid may flow. The thermal sensor500 is in electrical communication with a signal-conditioning element506, which may be embedded in the substrate 502 or may be remotelylocated. The signal-conditioning element 506 receives the signal fromthe thermal sensor 500 and modifies it by means such as amplifying itand filtering it to reduce noise. FIG. 57 also depicts a thermal sensor508 located at an alternate location on the surface where it is directlyexposed to the fluid flow.

[0250]FIG. 58 shows a configuration of a thermal sensor 500 adjacent toa separate heating element 510. The thermal sensor 500 and the heatingelement 510 are embedded in a substrate 502 adjacent to a surface 504over which a fluid may flow. In an alternate embodiment, one or moreadditional thermal sensors may be adjacent the heating element and mayprovide for increased signal sensitivity. The thermal sensor 500 is inelectrical communication with a signal-conditioning element 506, whichmay be embedded in the substrate 502 or may be remotely located.

[0251] The signal-conditioning element 506 receives the signal from thethermal sensor 500 and modifies it by means such as amplifying it andfiltering it to reduce noise. The heating element 510 is in electricalcommunication with a power supply and control element 512, which may beembedded in the substrate 502 or may be remotely located. The powersupply and control element 512 provides a controlled source of voltageand current to the heating element 510.

[0252]FIG. 59 depicts a configuration of thermal sensors 500 havingthree thermal sensor/heating element pairs (500/510), or detectorelements, (with associated signal conditioning elements 506 and powersupply and control elements 512 as described in FIG. 58) embedded in asubstrate 502 near each other alongside a surface 504. The figuredepicts the thermal sensors 500 arranged in a linear fashion parallel tothe surface 504, but any operable configuration may be used. Inalternate embodiments, fewer than three or more than three thermalsensor/heating element pairs (500/510) may be used to indicate thearrival of fluid flowing across a surface 504. In other embodiments,self-heating thermal sensors are used, eliminating the separate heatingelements.

[0253] Embodiments of the present invention provide a simple andaccurate methodology for detecting the arrival of a fluid at a definedlocation. Such detection can be particularly useful to define the zero-or start-time of a timing cycle for measuring rate-based reactions. Thiscan be used in biochemical assays to detect a variety of analytespresent in a variety of types of biological specimens or fluids and forrate-based reactions such as enzymatic reactions. Examples of relevantfluids include, blood, serum, plasma, urine, cerebral spinal fluid,saliva, enzymatic substances and other related substances and fluidsthat are well known in the analytical and biomedical art. The reactionchemistry for particular assays to analyze biomolecular fluids isgenerally well known, and selection of the particular assay used willdepend on the biological fluid of interest.

[0254] Assays that are relevant to embodiments of the present inventioninclude those that result in the measurement of individual analytes orenzymes, e.g., glucose, lactate, creatinine kinase, etc, as well asthose that measure a characteristic of the total sample, for example,clotting time (coagulation) or complement-dependent lysis. Otherembodiments for this invention provide for sensing of sample addition toa test article or arrival of the sample at a particular location withinthat article.

[0255] Referring now to FIG. 60, a substrate 502 defines a channel 520having an interior surface 522 over which fluid may flow. An analysissite 524 is located within the channel 520 where fluid flowing in thechannel 520 may contact the analysis site 524. In various embodiments,the analysis site 524 may alternatively be upon the interior surface522, recessed into the substrate 502, or essentially flush with theinterior surface 522. FIG. 60, depicts several possible locations forthermal sensors relative the substrate, the channel, and the analysissite; also, other locations may be useful and will depend upon thedesign of the device, as will be apparent to those of skill in art.

[0256] In use, thermal sensors may be omitted from one or more of thelocations depicted in FIG. 60, depending on the intended design. Arecess in the analysis site 524 may provide the location for a thermalsensor 526, as may the perimeter of the analysis site provide thelocation for a thermal sensor 528. One or more thermal sensors 530, 532,534 may be located on the upstream side of the analysis site 524 (asfluid flows from right to left in FIG. 60), or one or more thermalsensors 536, 538, 540 may be located on the downstream side of theanalysis site 524.

[0257] The thermal sensor may be embedded in the substrate near thesurface, as thermal sensor 542 is depicted. In various otherembodiments, the thermal sensor(s) may be located upon the interiorsurface, recessed into the interior surface, or essentially flush withthe interior surface. Each thermal sensor may also be associated with asignal conditioning element, heating element, and power supply andcontrol elements, as described above, and a single signal conditioningelement, heating element, or power supply and control element may beassociated with more than one thermal sensor.

[0258]FIG. 61 shows possible positions for thermal sensors relative toanalysis sites 524 arranged in an array on a surface 556. A recess inthe analysis site 524 may provide the location for a thermal sensor 544,as may the perimeter of the analysis site provide the location for athermal sensor 546. The edge of the surface surrounding the array ofanalysis sites may provide the position for one or more thermal sensors548. Thermal sensors may be positioned between analysis sites in aparticular row 550 or column 552 of the array, or may be arranged on thediagonal 554.

[0259] In various embodiments, the thermal sensor(s) may be may beembedded in the substrate near the surface or may be located upon thesurface, recessed into the surface, or essentially flush with thesurface. Each thermal sensor may also be associated with a signalconditioning elements, heating elements, and power supply and controlelements, as described above, and a single signal conditioning element,heating element, or power supply and control element may be associatedwith more than one thermal sensor.

[0260] The use of small thermal sensors can be useful in miniaturizedsystems, such as microfluidic devices, which perform biomolecularanalyses on very small fluid samples. Such analyses generally includepassing a biomolecular fluid through, over, or adjacent to an analysissite and result in information about the biomolecular fluid beingobtained through the use of reagents and/or test circuits and/orcomponents associated with the analysis site.

[0261]FIG. 62 depicts several possible configurations of thermal sensorsrelative to channels and analysis sites. The device schematicallydepicted in FIG. 62 may be, e.g., a microfluidic device for analyzing asmall volume of a sample fluid, e.g. a biomolecular fluid. The devicehas a sample reservoir 560 for holding a quantity of a sample fluid. Thesample fluid is introduced to the sample reservoir 560 via a sampleinlet port 562 in fluid communication with the sample reservoir 560. Athermal sensor 564 is located in or near the sample inlet port 562. Aprimary channel 566 originates at the sample reservoir 560 andterminates at an outflow reservoir 568.

[0262] One or more supplemental reservoirs 570 are optionally presentand are in fluid communication with the primary channel 566 via one ormore supplemental channels 572, which lead from the supplementalreservoir 570 to the primary channel 566. The supplemental reservoir 570functions to hold fluids necessary for the operation of the assay, suchas reagent solutions, wash solutions, developer solutions, fixativesolutions, et cetera. In the primary channel 566 at a predetermineddistance from the sample reservoir 560, an array of analysis sites 574is present.

[0263] Thermal sensors are located directly upstream (as fluid flowsfrom right to left in the figure) from the array 576 and directlydownstream from the array 578. Thermal sensors are also located in theprimary channel adjacent to where the primary channel originates at thesample reservoir 580 and adjacent to where the primary channelterminates at the outflow reservoir 582. The supplemental channelprovides the location for another thermal sensor 584.

[0264] When the device is in operation, the thermal sensor 564 locatedin or near the sample inlet port 562 is used to indicate the arrival ofthe sample fluid, e.g. the biomolecular fluid, in the local environmentof the thermal sensor, as described herein, and thus providesconfirmation that the sample fluid has successfully been introduced intothe device. The thermal sensor 580 located in the primary channel 566adjacent to where the primary channel 566 originates at the samplereservoir 560 produces a signal indicating that sample fluid has startedto flow from the sample reservoir 560 into the primary channel 566. Thethermal sensors 576 in the primary channel 566 just upstream from thearray of analysis sites 574 may be used to indicate that the fluidsample is approaching the array 574. Similarly, the thermal sensors 578in the primary channel 566 just downstream from the array of analysissites 574 may be used to indicate that the fluid sample has advancedbeyond the array 574 and has thus contacted each analysis site.

[0265] The thermal sensor 584 in the supplemental channel 572 providesconfirmation that the fluid contained within the supplemental reservoir570 has commenced to flow therefrom. The thermal sensor 582 in theprimary channel 566 adjacent to where the primary channel 566 terminatesat the outflow reservoir 568 indicates when sample fluid arrives nearthe outflow reservoir 568, which may then indicate that sufficientsample fluid has passed over the array of analysis sites 574 and thatthe analysis at the analysis sites is completed.

[0266] Embodiments of the invention provide for the use of a thermalsensor to detect the arrival of the fluid sample at a determined region,such as an analysis site, in the local environment of the thermal sensornear the thermal sensor. A variety of thermal sensors may be used.Thermistors are thermally-sensitive resistors whose prime function is todetect a predictable and precise change in electrical resistance whensubjected to a corresponding change in temperature Negative TemperatureCoefficient (NTC) thermistors exhibit a decrease in electricalresistance when subjected to an increase in temperature and PositiveTemperature Coefficient (PTC) thermistors exhibit an increase inelectrical resistance when subjected to an increase in temperature.

[0267] A variety of thermistors have been manufactured for over thecounter use and application. Thermistors are capable of operating overthe temperature range of −100 degrees to over 600 degrees Fahrenheit.Because of their flexibility, thermistors are useful for application tomicro-fluidics and temperature measurement and control.

[0268] A change in temperature results in a corresponding change in theelectrical resistance of the thermistor. This temperature change resultsfrom either an external transfer of heat via conduction or radiationfrom the sample or surrounding environment to the thermistor, or as aninternal application of heat due to electrical power dissipation withinthe device. When a thermistor is operated in “self-heating” mode, thepower dissipated in the device is sufficient to raise its temperatureabove the temperature of the local environment, which in turn moreeasily detects thermal changes in the conductivity of the localenvironment.

[0269] Thermistors are frequently used in “self heating” mode inapplications such as fluid level detection, airflow detection andthermal conductivity materials characterization. This mode isparticularly useful in fluid sensing, since a self-heating conductivitysensor dissipates significantly more heat in a fluid or in a moving airstream than it does in still air.

[0270] Embodiments of the invention may be designed such that thethermal sensor is exposed directly to the sample. However, it may alsobe embedded in the material of the device, e.g., in the wall of achannel meant to transport the sample. The thermal sensor may be coveredwith a thin coating of polymer or other protective material.

[0271] Embodiments of the device need to establish a baseline orthreshold value of a monitored parameter such as temperature. Ideallythis is established during the setup process. Once fluid movement hasbeen initiated, the device continuously monitors for a significantchange thereafter. The change level designated as “significant” isdesigned as a compromise between noise rejection and adequatesensitivity. The actual definition of the “zero- or start-time” may alsoinclude an algorithm determined from the time history of the data, i.e.,it can be defined ranging from the exact instant that a simple thresholdis crossed, to a complex mathematical function based upon a timesequence of data.

[0272] In use, a signal is read from a thermal sensor in the absence ofthe sample or fluid. The fluid sample is then introduced. The sampleflows to or past the site of interest in the local environment of thethermal sensor, and the thermal sensor registers the arrival of thesample. The site of interest may include an analysis site forconducting, e.g., an enzymatic assay. Measuring the arrival of fluid atthe site of interest thus indicates the zero- or start-time of thereaction to be performed. For detection of fluid presence, these sitesmay be any of a variety of desired locations along the fluidic pathway.Embodiments of the invention are particularly well suited to amicrofluidic cartridge or platform, which provide the user with anassurance that a fluid sample has been introduced and has flowed to theappropriate locations in the platform.

[0273] A rate-based assay must measure both an initiation time, and somenumber of later time points, one of which is the end-point of the assay.Therefore, baseline or threshold value can be established, and thencontinuously monitored for a significant change thereafter; one suchchange is the arrival of the fluid sample that initiates the enzymereaction. Baseline values are frequently established during the devicesetup process. The threshold is designed as a compromise between noiserejection and adequate sensitivity. The defined zero- or “start-time”can be defined ranging from the exact instant that a simple threshold iscrossed, to the value algorithmically determined using a filter based ona time sequence of data.

[0274] Embodiments of the invention accomplish this in a variety ofways. In one embodiment, an initial temperature measurement is made at athermal sensor without the sample present. The arrival of a samplechanges causes the thermal sensor to register a new value. These valuesare then compared.

[0275] Another embodiment measures the change in thermal properties(such as thermal conductivity or thermal capacity) in the localenvironment of a thermal sensor caused by the arrival of a fluid sample.In general this is the operating principle of a class of devices knownas “thermal conductivity sensors” or “heat flux sensors”. At least twohardware implementations have been used and are described above. Oneimplementation utilizes a thermal sensor in a “self-heating mode.” In“self-heating mode,” a self-heating thermal sensor may utilize apositive temperature coefficient thermistor placed in or near the flowchannel, e.g. located in the wall of the flow channel.

[0276] An electrical current is run through the thermistor, causing theaverage temperature of the thermistor to rise above that of thesurrounding environment. The temperature can be determined from theelectrical resistance, since it is temperature dependent. When fluidflows through the channel, it changes the local thermal conductivitynear the thermistor (usually to become higher) and this causes a changein the average temperature of the thermistor. It also changes thethermal capacity, which modifies the thermal dynamic response. Thesechanges give rise to a signal, which can be detected electronically bywell-known means, and the arrival of the fluid can thereby be inferred.

[0277] A second hardware implementation requires a separate heatingelement in or near the flow channel, plus a thermal sensor arrangementin close proximity. Passing a current through the element provides heatto the local environment and establishes a local temperature detected bythe thermocouple device. This temperature or its dynamic response isaltered by the arrival of the fluid or blood in or near the localenvironment, similar to the previously described implementation, and theevent is detected electronically.

[0278] The heating element can be operated in a controlled input mode,which may include controlling one or more of the followingparameters—applied current, voltage or power—in a prescribed manner.When operating in controlled input mode, fluctuations of the temperatureof the thermal sensor are monitored in order to detect the arrival ofthe fluid.

[0279] Alternatively, the heating element can be operated in such afashion as to control the temperature of the thermal sensor in aprescribed manner. In this mode of operation, the resulting fluctuationsin one or more of the input parameters to the heating element (appliedcurrent, voltage, and power) can be monitored in order to detect thearrival of the fluid.

[0280] In either of the above-described operating modes, the prescribedparameter can be held to a constant value or sequence of values that areheld constant during specific phases of operation of the device. Theprescribed parameter can also varied as a known function or waveform intime.

[0281] The change in the monitored parameters caused by the arrival ofthe fluid can be calculated in any of a number of ways, using methodswell known in the art of signal processing. The signal processingmethods allow the relation of the signal received prior to arrival ofthe fluid with the signal received upon arrival of the fluid to indicatethat the fluid has arrived. For example, and after suitable signalfiltering is applied, changes in the monitored value or the rate ofchange of the value of the signal can be monitored to detect the arrivalof the fluid. Additionally, the arrival of fluid will cause a dynamicchange in the thermodynamic properties of the local environment, such asthermal conductivity or thermal capacity. When the input parameter is atime varying function this change of thermodynamic properties will causea phase shift of the measured parameter relative to the controlledparameter. This phase shift can be monitored to detect the arrival ofthe fluid.

[0282] It should also be noted that sensitivity to thermal noise andoperating power levels could be reduced in these either of these modesof operation by a suitable choice of time-varying waveforms for theprescribed parameter, together with appropriate and well-known signalprocessing methods applied to the monitored parameters. However, thesepotential benefits may come at the cost of slower response time.

[0283] Referring to FIG. 63, an alternative embodiment of a tissuepenetration sampling device is shown which incorporates disposablesampling module 590, a lancet driver 591, and an optional modulecartridge 592 are shown. The optional module cartridge comprises a casebody 593 having a storage cavity 594 for storing sampling modules 590. Acover to this cavity has been left out for clarity. The cartridgefurther comprises a chamber 595 for holding the lancet driver 591. Thelancet driver has a preload adjustment knob 596, by which the triggerpoint of the lancet driver may be adjusted. This insures a reproducibletension on the surface of the skin for better control of the depth ofpenetration and blood yield. In one embodiment, the sampling module 590is removably attached to the lancet driver 591, as shown, so that thesampling module 590 is disposable and the lancet driver 591 is reusable.In an alternative embodiment, the sampling module and lancet driver arecontained within a single combined housing, and the combination sampleacquisition module/lancet driver is disposable. The sampling module 590includes a sampling site 597, preferably having a concave depression598, or cradle, that can be ergonomically designed to conform to theshape of a user's finger or other anatomical feature (not shown).

[0284] The sampling site further includes an opening 599 located in theconcave depression. The lancet driver 591 is used to fire a lancetcontained within and guided by the sampling module 590 to create anincision on the user's finger when the finger is placed on the samplingsite 597. In one embodiment, the sampling site forms a substantiallyairtight seal at the opening when the skin is firmly pressed against thesampling site; the sampling site may additionally have a soft,compressible material surrounding the opening to further limitcontamination of the blood sample by ambient air. “Substantiallyairtight” in this context means that only a negligible amount of ambientair may leak past the seal under ordinary operating conditions, thesubstantially airtight seal allowing the blood to be collectedseamlessly.

[0285] Referring to FIGS. 64 and 65, the lancet 600 is protected in theintegrated housing 601 that provides a cradle 602 for positioning theuser's finger or other body part, a sampling port 603 within the cradle602, and a sample reservoir 603′ for collecting the resulting bloodsample. The lancet 600 is a shaft with a distal end 604 sharpened toproduce the incision with minimal pain. The lancet 600 further has anenlarged proximal end 605 opposite the distal end. Similar lancets arecommonly known in the art.

[0286] Rather than being limited to a shaft having a sharp end, thelancet may have a variety of configurations known in the art, withsuitable modifications being made to the system to accommodate suchother lancet configurations, such configurations having a sharpinstrument that exits the sampling port to create a wound from which ablood sample may be obtained.

[0287] In the figures, the lancet 600 is slidably disposed within alancet guide 606 in the housing 601, and movement of the lancet 600within the lancet guide 606 is closely controlled to reduce lateralmotion of the lancet, thereby reducing the pain of the lance stick. Thesample acquisition module also includes a return stop 613, which retainsthe lancet within the sample acquisition module. The sampling module hasan attachment site 615 for attachment to the lancet driver.

[0288] The sampling module further includes a depth selector allowingthe user to select one of several penetration depth settings. The depthselector is shown as a multi-position thumbwheel 607 having a graduatedsurface. By rotating the thumbwheel 607, the user selects which part ofthe graduated surface contacts the enlarged proximal end 605 of thelancet to limit the movement of the lancet 600 within the lancet guide606.

[0289] The thumbwheel is maintained in the selected position by aretainer 608 having a protruding, rounded surface which engages at leastone of several depressions 609 (e.g. dimples, grooves, or slots) in thethumbwheel 607. The depressions 609 are spatially aligned to correspondwith the graduated slope of the thumbwheel 607, so that, when thethumbwheel 607 is turned, the depth setting is selected and maintainedby the retainer 608 engaging the depression 609 corresponding to theparticular depth setting selected.

[0290] In alternate embodiments, the retainer may be located on thedepth selector and the depressions corresponding to the depth settinglocated on the housing such that retainer may functionally engage thedepressions. Other similar arrangements for maintaining components inalignment are known in the art and may be used. In further alternateembodiments, the depth selector may take the form of a wedge having agraduated slope, which contacts the enlarged proximal end of the lancet,with the wedge being retained by a groove in the housing.

[0291] The sample reservoir 603′ includes an elongate, rounded chamber610 within the housing 601 of the sample acquisition module. The chamber610 has a flat or slightly spherical shape, with at least one side ofthe chamber 610 being formed by a smooth polymer, preferably absent ofsharp corners. The sample reservoir 603′ also includes a sample inputport 611 to the chamber 610, which is in fluid communication with thesampling port 603, and a vent 612 exiting the chamber.

[0292] A cover (not shown), preferably of clear material such asplastic, positions the lancet 600 and closes the chamber 603′, formingan opposing side of the chamber 603′. In embodiments where the cover isclear, the cover may serve as a testing means whereby the sample may beanalyzed in the reservoir via optical sensing techniques operatingthrough the cover. A clear cover will also aid in determining byinspection when the sample reservoir is full of the blood sample.

[0293]FIG. 66 shows a portion of the sampling module illustrating analternate embodiment of the sample reservoir. The sample reservoir has achamber 616 having a sample input port 617 joining the chamber 616 to ablood transport capillary channel 618; the chamber 616 also has a vent619. The chamber has a first side 620 that has a flat or slightlyspherical shape absent of sharp corners and is formed by a smoothpolymer. An elastomeric diaphragm 621 is attached to the perimeter ofthe chamber 616 and preferably is capable of closely fitting to thefirst side of the chamber 620.

[0294] To control direction of blood flow, the sample reservoir isprovided with a first check valve 622 located at the entrance 617 of thesample reservoir and a second check valve 623 leading to an exit channel624 located at the vent 619. Alternately, a single check valve (at thelocation 622) may be present controlling both flow into the chamber 616via the blood transport capillary channel 618 and flow out of thechamber 616 into an optional alternate exit channel 625. The samplereservoir has a duct 626 connecting to a source of variable pressurefacilitating movement of the diaphragm 621.

[0295] When the diaphragm 621 is flexed away from the first side of thechamber 620 (low pressure supplied from the source via duct 626), thefirst check valve 622 is open and the second check valve 623 is closed,aspiration of the blood sample into the sample reservoir follows. Whenthe diaphragm 621 is flexed in the direction of the first side of thechamber 620 (high pressure supplied from the source via duct 626) withthe first check valve 622 closed and the second check valve 623 open,the blood is forced out of the chamber 616. The direction of movementand actuation speed of the diaphragm 621 can be controlled by thepressure source, and therefore the flow of the sample can be acceleratedor decelerated. This feature allows not only reduced damage to the bloodcells but also for the control of the speed by which the chamber 616 isfilled.

[0296] While control of the diaphragm 621 via pneumatic means isdescribed in this embodiment, mechanical means may alternately be used.Essentially, this micro diaphragm pump fulfills the aspiration, storage,and delivery functions. The diaphragm 621 may be used essentially as apump to facilitate transfer of the blood to reach all areas required.Such required areas might be simple sample storage areas furtherdownstream for assaying or for exposing the blood to a chemical sensoror other testing means. Delivery of the blood may be to sites within thesampling module or to sites outside the sampling module, i.e. a separateanalysis device.

[0297] In an alternate embodiment, a chemical sensor or other testingmeans is located within the sampling module, and the blood is deliveredto the chemical sensor or other testing means via a blood transferchannel in fluid communication with the sample reservoir. The componentsof the sampling module may be injection molded and the diaphragm may befused or insertion molded as an integral component.

[0298]FIG. 67 depicts a portion of the disposable sampling modulesurrounding the sampling port 627, including a portion of the samplingsite cradle surface 628. The housing of the sampling module includes aprimary sample flow channel 629 that is a capillary channel connectingthe sample input port to the sample reservoir. The primary sample flowchannel 629 includes a primary channel lumenal surface 630 and a primarychannel entrance 631, the primary channel entrance 631 opening into thesample input port 627. The sampling module may optionally include asupplemental sample flow channel 632 that is also a capillary channelhaving a supplemental channel lumenal surface 633 and a supplementalchannel entrance 634, the supplemental channel entrance 634 opening intothe sample input port 627.

[0299] The primary sample flow channel 629 has a greater cross-sectionalarea than the supplemental sample flow channel 632, preferably by atleast a factor of two. Thus, the supplemental sample flow channel 632draws fluid faster than the primary sample flow channel 629. When thefirst droplet of blood is received into the sample input port 627, themajority of this droplet is drawn through the supplemental sample flowchannel 632. However, as the blood continues to flow from the incisioninto the sample input port 627, most of this blood is drawn through theprimary sample flow channel 629, since the supplemental sample flowchannel 632 is of limited capacity and is filled or mostly filled withthe first blood droplet. This dual capillary channel configuration isparticularly useful in testing where there is a concern withcontamination of the sample, e.g. with debris from the lancet strike or(particularly in the case of blood gas testing) with air.

[0300] In order to improve blood droplet flow, some priming or wickingof the surface with blood is at times necessary to begin the capillaryflow process. Portions of the surfaces of the sample input port 627 andthe primary and supplemental (if present) sample flow channels 629, 632are treated to render those surfaces hydrophilic. The surfacemodification may be achieved using mechanical, chemical, corona, orplasma treatment. Examples of such coatings and methods are marketed byAST Products (Billerica, Mass.) and Spire Corporation (Bedford, Mass.).

[0301] However, a complete blanket treatment of the surface could provedetrimental by causing blood to indiscriminately flow all over thesurface and not preferentially through the capillary channel(s). Thisultimately will result in losses of blood fluid. The particular surfaceswhich receive the treatment are selected to improve flow of blood froman incised finger on the sampling site cradle surface 628 through thesample input port 627 and at least one of the sample flow channels 629,632 to the sample reservoir. Thus, the treatment process should bemasked off and limited only to the selected surfaces. The maskingprocess of selectively modifying the sampling surface from hydrophobicto hydrophilic may be done with mechanical masking techniques such aswith metal shielding, deposited dielectric or conductive films, orelectrical shielding means.

[0302] In some embodiments, the treated surfaces are limited to one ormore of the following: the surface of the sampling port which liesbetween the sampling site cradle surface and the primary andsupplemental sample flow channel, the surface immediately adjacent tothe entrances to the primary and/or supplemental sample flow channels631, 634 (both within the sample input port and within the sample flowchannel), and the lumenal surface of the primary and/or supplementalsample flow channels 630, 633.

[0303] Upon exiting the incision blood preferentially moves through thesample input port 627 into the supplementary sample flow channel 632 (ifpresent) and into the primary sample flow channel 629 to the samplereservoir, resulting in efficient capture of the blood. Alternatively,the substrate material may be selected to be hydrophilic or hydrophobic,and a portion of the surface of the substrate material may be treatedfor the opposite characteristic.

[0304] In an embodiment, FIG. 67 a membrane 635 at the base of thesample input port 627 is positioned between the retracted sharpeneddistal end of the lancet 636 and the entrance to the sample flowchannels 631, 634. The membrane 635 facilitates the blood sample flowthrough the sample flow channels 629, 632 by restricting the blood fromflowing into the area 636 surrounding the distal end of the lancet 637.The blood thus flows preferentially into the sample reservoir. In anembodiment, the membrane 635 is, treated to have a hydrophobiccharacteristic. In another embodiment, the membrane 635 is made ofpolymer-based film 638 that has been coated with a silicone-based gel639.

[0305] For example, the membrane structure may comprise a polymer-basedfilm 638 composed of polyethylene terephthalate, such as the film soldunder the trademark MYLAR. The membrane structure may further comprise athin coating of a silicone-based gel 639 such as the gel sold under thetrademark SYLGARD on at least one surface of the film. The usefulness ofsuch a film is its ability to reseal after the lancet has penetrated itwithout physically affecting the lancet's cutting tip and edges. TheMYLAR film provides structural stability while the thin SYLGARD siliconelaminate is flexible enough to retain its form and close over the holemade in the MYLAR film. Other similar materials fulfilling thestructural stability and flexibility roles may be used in themanufacture of the membrane in this embodiment.

[0306] The membrane 635 operates to allow the sharpened distal end ofthe lancet 637 to pierce the membrane as the sharpened distal end of thelancet 637 travels into and through the sample input port 627. In anembodiment, the silicone-based gel 639 of the membrane 635 automaticallyseals the cut caused by the piercing lancet. Therefore, after anincision is made on a finger of a user, the blood from the incision isprevented from flowing through the membrane 635, which aids the blood totravel through the primary sample flow channel 629 to accumulate withinthe sample reservoir. Thus the film prevents any blood from flowing intothe lancet device assembly, and blood contamination and loss into thelancet device mechanism cavity are prevented. Even without the resealinglayer 639, the hydrophobic membrane 635 deters the flow of blood acrossthe membrane 635, resulting in improved flow through the primary sampleflow channel 629 and reduced or eliminated flow through the piercedmembrane 635.

[0307] FIGS. 68-70 illustrate one implementation of a lancet driver 640at three different points during the use of the lancet driver. In thisdescription of the lancet driver, proximal indicates a positionrelatively close to the site of attachment of the sampling module;conversely, distal indicates a position relatively far from the site ofattachment of the sampling module. The lancet driver has a driver handlebody 641 defining a cylindrical well 642 within which is a preloadspring 643. Proximal to the preload spring 643 is a driver sleeve 644,which closely fits within and is slidably disposed within the well 642.The driver sleeve 644 defines a cylindrical driver chamber 645 withinwhich is an actuator spring 646. Proximal to the actuator spring 646 isa plunger sleeve 647, which closely fits within and is slidably disposedwithin the driver sleeve 644.

[0308] The driver handle body 641 has a distal end 648 defining athreaded passage 649 into which a preload screw 650 fits. The preloadscrew defines a counterbore 651. The preload screw 650 has a distal end652 attached to a preload adjustment knob 653 and a proximal end 654defining an aperture 655. The driver sleeve 644 has a distal end 656attached to a catch fitting 657. The catch fitting 657 defines a catchhole 658. The driver sleeve 644 has a proximal end 659 with a slopedring feature 660 circling the interior surface of the driver sleeve'sproximal end 659.

[0309] The lancet driver includes a plunger stem 660 having a proximalend 661 and a distal end 662. At its distal end 662, an enlarged plungerhead 663 terminates the plunger stem 660. At its proximal end 661, theplunger stem 660 is fixed to the plunger tip 667 by adhesively bonding,welding, crimping, or threading into a hole 665 in the plunger tip 667.A plunger hook 665 is located on the plunger stem 660 between theplunger head 663 and the plunger tip 667. The plunger head 663 isslidably disposed within the counterbore 651 defined by the preloadscrew 650. The plunger stem 660 extends from the plunger head 663,through the aperture 655 defined by the proximal end 654 of the preloadscrew, thence through the hole 658 in the catch fitting 657, to thejoint 664 in the plunger tip 667. For assembly purposes, the plungerbase joint 664 may be incorporated into the plunger sleeve 647, and theplunger stem 660 attached to the plunger base 664 by crimping, swaging,gluing, welding, or some other means. Note that the lancet driver 640could be replaced with any of the controlled electromagnetic driversdiscussed above.

[0310] The operation of the tissue penetration sampling device may bedescribed as follows, with reference to FIGS. 63-70. In operation, afresh sampling module 590 is removed from the storage cavity 594 andadjusted for the desired depth setting using the multi-positionthumbwheel 607. The sampling module 590 is then placed onto the end ofthe lancet driver 591. The preload setting may be checked, but will notchange from cycle to cycle once the preferred setting is found; ifnecessary, the preload setting may be adjusted using the preloadadjustment knob 596.

[0311] The combined sampling module and lancet driver assembly is thenpressed against the user's finger (or other selected anatomical feature)in a smooth motion until the preset trigger point is reached. Thetrigger point corresponds to the amount of preload force that needs tobe overcome to actuate the driver to drive the lancet towards the skin.The preload screw allows the preload setting to be adjusted by the usersuch that a consistent, preset (by the user) amount of preload force isapplied to the sampling site 597 each time a lancing is performed.

[0312] When the motion to press the assembly against the user's fingeris begun (see FIG. 68), the plunger hook 665 engages catch fitting 657,holding the actuator spring 646 in a cocked position while the forceagainst the finger builds as the driver sleeve 644 continues to compressthe preload spring 643. Eventually (see FIG. 69) the sloped back of theplunger hook 665 slides into the hole 655 in the proximal end of thepreload screw 654 and disengages from the catch fitting 657. The plungersleeve 647 is free to move in a proximal direction once the plunger hook665 releases, and the plunger sleeve 647 is accelerated by the actuatorspring 646 until the plunger tip 667 strikes the enlarged proximal endof the lancet 212.

[0313] Upon striking the enlarged proximal end of the lancet 605, theplunger tip 667 of the actuated lancet driver reversibly engages theenlarged proximal end of the lancet 605. This may be accomplished bymechanical means, e.g. a fitting attached to the plunger tip 667 thatdetachably engages a complementary fitting on the enlarged proximal endof the lancet 605, or the enlarged proximal end of the lancet 605 may becoated with an adhesive that adheres to the plunger tip 667 of theactuated lancet driver. Upon being engaged by the plunger tip 667, thelancet 600 slides within the lancet guide 606 with the sharpened distalend of the lancet 604 emerging from the housing 601 through the samplingport 603 to create the incision in the user's finger.

[0314] At approximately the point where the plunger tip 667 contacts theenlarged proximal end of the lancet 605, the actuator spring 646 is atits relaxed position, and the plunger tip 667 is traveling at itsmaximum velocity. During the extension stroke, the actuator spring 646is being extended and is slowing the plunger tip 667 and lancet 600. Theend of stroke occurs (see FIG. 70) when the enlarged proximal end of thelancet 605 strikes the multi-position thumbwheel 607.

[0315] The direction of movement of the lancet 600 is then reversed andthe extended actuator spring then quickly retracts the sharpened distalend of the lancet 604 back through the sampling port 603. At the end ofthe return stroke, the lancet 600 is stripped from the plunger tip 667by the return stop 613. The adhesive adheres to the return stop 613retaining the lancet in a safe position.

[0316] As blood seeps from the wound, it fills the sample input port 603and is drawn by capillary action into the sample reservoir 603′. In thisembodiment, there is no reduced pressure or vacuum at the wound, i.e.the wound is at ambient air pressure, although embodiments which drawthe blood sample by suction, e.g. supplied by a syringe or pump, may beused. The vent 612 allows the capillary action to proceed until theentire chamber is filled, and provides a transfer port for analysis ofthe blood by other instrumentation. The finger is held against thesample acquisition module until a complete sample is observed in thesample reservoir.

[0317] As the sampling module 600 is removed from the lancet driver 591,a latch 614 that is part of the return stop 613 structure engages asloped ring feature 660 inside the lancet driver 591. As the lancetdriver 591 is removed from the sampling module 600, the latch forces thereturn stop 613 to rotate toward the lancet 600, bending it to lock itin a safe position, and preventing reuse.

[0318] As the sampling module 600 is removed from the lancet driver 591,the driver sleeve 644 is forced to slide in the driver handle body 641by energy stored in the preload spring 643. The driver sleeve 644,plunger sleeve 647, and actuator spring 646 move outward together untilthe plunger head 663 on the plunger stem 660 contacts the bottom of thecounterbore 651 at the proximal end of the preload screw 654. Thepreload spring 643 continues to move the driver sleeve 644 outwardcompressing the actuator spring 646 until the plunger hook 665 passesthrough the hole 658 in the catch fitting 657. Eventually the twosprings reach equilibrium and the plunger sleeve 647 comes to rest in acocked position.

[0319] After the sampling module 600 is removed from the lancet driver591, it may be placed in a separate analysis device to obtain bloodchemistry readings. In a preferred embodiment, the integrated housing601 or sample reservoir 603′ of the sampling module 600 contains atleast one biosensor, which is powered by and/or read by the separateanalysis device. In another embodiment, the analysis device performs anoptical analysis of the blood sample directly through the clear plasticcover of the sampling module.

[0320] Alternatively, the blood sample may be transferred from thesampling module into an analysis device for distribution to variousanalysis processes.

[0321] Alternate embodiments of the invention offer improved successrates for sampling, which reduces the needless sacrifice of a samplestorage reservoir or an analysis module due to inadequate volume fill.Alternate embodiments allow automatic verification that sufficient bloodhas been collected before signaling the user (e.g. by a signal light oran audible beep) that it is okay to remove the skin from the samplingsite.

[0322] In such alternate embodiments, one or more additional lancet(s)(denoted backup lancets) and/or lancet driver(s) (denoted backup lancetdrivers) and/or sample reservoir(s) (denoted backup sample reservoirs)are present with the “primary” sampling module.

[0323] In one such preferred embodiment, following detection ofinadequate blood sample volume (e.g., by light or electronic methods), abackup sampling cycle is initiated automatically. The “backup samplingcycle” includes disconnecting the primary sample reservoir via a simplevalving system, bringing the backup components online, lancing of theskin, collection of the blood, and movement of the blood to the backupsample reservoir.

[0324] Blood flows into the backup sample reservoir until the requiredvolume is obtained. The cycle repeats itself, if necessary, until thecorrect volume is obtained. Only then is the sample reservoir madeavailable as a source of sampled blood for use in measurements or forother applications. The series of reservoirs and/or lancets and/orlancet drivers may easily be manufactured in the same housing and betransparent to the user.

[0325] In one embodiment, up to three sample reservoirs (the primaryplus two backup) are present in a single sample acquisition module, eachconnected via a capillary channel/valving system to one or more samplingports. Another embodiment has four sample reservoirs (the primary plusthree backup) present in a single sample acquisition module, eachconnected via a capillary channel/valving system to one or more samplingports. With three or four sample reservoirs, at least an 80% samplingsuccess rate can be achieved for some embodiments.

[0326] Another embodiment includes a miniaturized version of the tissuepenetration sampling device. Several of the miniature lancets may belocated in a single sampling site, with corresponding sample flowchannels to transfer blood to one or more reservoirs. The sample flowchannels may optionally have valves for controlling flow of blood. Thedevice may also include one or more sensors, such as the thermal sensorsdiscussed above, for detecting the presence of blood, e.g. to determineif a sufficient quantity of blood has been obtained. In such anembodiment, the disposable sampling module, the lancet driver, and theoptional module cartridge will have dimensions no larger than about 150mm long, 60 mm wide, and 25 mm thick.

[0327] In other embodiments, the size of the tissue penetration samplingdevice including the disposable sampling module, the lancet driver, andthe optional cartridge will have dimensions no larger than about 100 mmlong, about 50 mm wide, and about 20 mm thick, and in still otherembodiments no larger than about 70 mm long, about 30 mm wide, and about10 mm thick. The size of the tissue penetration sampling deviceincluding the disposable sampling module, the lancet driver, and theoptional cartridge will generally be at least about 10 mm long, about 5mm wide, and about 2 mm thick.

[0328] In another miniature embodiment, the dimensions of the lancetdriver without the cartridge or sampling module are no larger than about80 mm long, 10 mm wide, and 10 mm thick, or specifically no larger thanabout 50 mm long, 7 mm wide, and 7 mm thick, or even more specificallyno larger than about 15 mm long, 5 mm wide, and 3 mm thick; dimensionsof the lancet driver without the cartridge or sampling module aregenerally at least about 1 mm long, 0.1 mm wide, and 0.1 mm thick, orspecifically at least about 2 mm long, 0.2 mm wide, and 0.2 mm thick, ormore specifically at least about 4 mm long, 0.4 mm wide, and 0.4 mmthick.

[0329] In yet another miniature embodiment, dimensions of the miniaturesampling module without the lancet driver or cartridge are no largerthan about 15 mm long, about 10 mm wide, and about 10 mm thick, or nolarger than about 10 mm long, about 7 mm wide, and about 7 mm thick, orno larger than about 5 mm long, about 3 mm wide, and about 2 mm thick;dimensions of the miniature sampling module without the lancet driver orcartridge are generally at least about 1 mm long, 0.1 mm wide, and 0.1mm thick, specifically at least about 2 mm long, 0.2 mm wide, and 0.2 mmthick, or more specifically at least about 4 mm long, 0.4 mm wide, and0.4 mm thick.

[0330] In another embodiment, the miniaturized sampling module and thelancet driver form a single unit having a shared housing, and thecombined sample acquisition module/lancet driver unit is disposable.Such a combined unit is no larger than about 80 mm long, about 30 mmwide, and about 10 mm thick, specifically no larger than about 50 mmlong, about 20 mm wide, and about 5 mm thick, more specifically, nolarger than about 20 mm long, about 5 mm wide, and about 3 mm thick; thecombined unit is generally at least about 2 mm long, about 0.3 mm wide,and about 0.2 mm thick, specifically at least about 4 mm long, 0.6 mmwide, and 0.4 mm thick, more specifically, at least about 8 mm long, 1mm wide, and 0.8 mm thick.

[0331] Referring to FIG. 71, another embodiment of a tissue penetrationsampling device is shown, incorporating a disposable sampling module 608cartridge and analyzer device 669 is shown. The analyzer device 669includes a deck 670 having a lid 671 attached to the deck by hingesalong the rear edge of the system 672. A readout display 673 on the lid671 functions to give the user information about the status of theanalyzer device 669 and/or the sampling module cartridge 668, or to givereadout of a blood test. The analyzer device 669 has several functionbuttons 674 for controlling function of the analyzer device 669 or forinputting information into the reader device 669. Alternatively, thereader device may have a touch-sensitive screen, an optical scanner, orother input means known in the art.

[0332] An analyzer device with an optical scanner may be particularlyuseful in a clinical setting, where patient information may be recordedusing scan codes on patients' wristbands or files. The analyzer readerdevice may have a memory, enabling the analyzer device to store resultsof many recent tests. The analyzer device may also have a clock andcalendar function, enabling the results of tests stored in the memory tobe time and date-stamped. A computer interface 675 enables records inmemory to be exported to a computer. The analyzer device 669 has achamber located between the deck 670 and the lid 671, which closelyaccommodates a sampling module cartridge 668. Raising the lid 671,allowing a sampling module cartridge 668 to be inserted or removed,accesses the chamber.

[0333]FIG. 72 is an illustration showing some of the features of anembodiment of a sampling module cartridge. The sampling module cartridge668 has a housing having an orientation sensitive contact interface formating with a complementary surface on the analyzer device. The contactinterface functions to align the sampling module cartridge with theanalyzer device, and also allows the analyzer device to rotate thesampling module cartridge in preparation for a new sampling event. Thecontact interface may take the form of cogs or grooves formed in thehousing, which mate with complementary cogs, or grooves in the chamberof the analyzer device.

[0334] The sampling module cartridge has a plurality of sampling sites678 on the housing, which are shown as slightly concave depressions nearthe perimeter of the sampling module cartridge 668. Each sampling sitedefines an opening 679 contiguous with a sample input port entering thesampling module. In an alternate embodiment, the sampling sites andsample input ports are located on the edge of the sampling modulecartridge. Optical windows 680 allow transmission of light into thesampling module cartridge for the purpose of optically reading testresults. Alternatively, sensor connection points allow transmission oftest results to the analyzer device via electrical contact. Access ports681, if present, allow transmission of force or pressure into thesampling module cartridge from the analyzer device. The access ports maybe useful in conjunction with running a calibration test or combiningreagents with sampled blood or other bodily fluids.

[0335] The described features are arranged around the sampling modulecartridge, and the sampling module cartridge is radially partitionedinto many sampling modules, each sampling module having the componentsnecessary to perform a single blood sampling and testing event. Aplurality of sampling modules are present on a sampling modulecartridge, generally at least ten sampling modules are present on asingle disposable sampling module cartridge; at least about 20, or moreon some embodiments, and at least about 34 sampling modules are presenton one embodiment, allowing the sampling module cartridge to bemaintained in the analyzer device for about a week before replacing witha new sampling module cartridge (assuming five sampling and testingevents per day for seven days). With increasing miniaturization, up toabout 100, or more preferably up to about 150, sampling modules may beincluded on a single sampling module cartridge, allowing up to a monthbetween replacements with new sampling module cartridges. It may benecessary for sampling sites to be located in several concentric ringsaround the sampling module cartridge or otherwise packed onto thehousing surface to allow the higher number of sampling modules on asingle sampling module cartridge.

[0336] In other embodiments, the sampling module cartridge may be anyother shape which may conveniently be inserted into a analyzer deviceand which are designed to contain multiple sampling modules, e.g. asquare, rectangular, oval, or polygonal shape. Each sampling module isminiaturized, being generally less than about 6.0 cm long by about 1.0cm wide by about 1.0 cm thick, so that thirty five more or lesswedge-shaped sampling modules can fit around a disk having a radius ofabout 6.0 cm. In some embodiments, the sampling modules can be muchsmaller, e.g. less than about 3.0 cm long by about 0.5 cm wide by about0.5 cm thick.

[0337]FIG. 73 depicts, in a highly schematic way, a single samplingmodule, positioned within the analyzer device. Of course, it will occurto the person of ordinary skill in the art that the various recitedcomponents may be physically arranged in various configurations to yielda functional system. FIG. 73 depicts some components, which might onlybe present in alternate embodiments and are not necessarily all presentin any single embodiment. The sampling module has a sample input port682, which is contiguous with an opening 683 defined by a sampling site684 on the cartridge housing 685. A lancet 686 having a lancet tip 687adjacent to the sample input port 682 is operably maintained within thehousing such that the lancet 686 can move to extend the lancet tip 687through the sample input port 682 to outside of the sampling modulecartridge.

[0338] The lancet 686 also has a lancet head 688 opposite the lancettip. The lancet 686 driven to move by a lancet driver 689, which isschematically depicted as a coil around the lancet 686. The lancetdriver 689 optionally is included in the sampling module cartridge aspictured or alternatively is external to the sampling module cartridge.The sampling module may further include a driver port 690 defined by thehousing adjacent to the lancet head 688—the driver port 690 allows anexternal lancet driver 691 access to the lancet 686.

[0339] In embodiments where the lancet driver 689 is in the samplingmodule cartridge, it may be necessary to have a driver connection point694 upon the housing accessible to the analyzer device. The driverconnection point 694 may be a means of triggering the lancet driver 689or of supplying motive force to the lancet driver 689, e.g. anelectrical current to an electromechanical lancet driver. Note that anyof the drivers discussed above, including controllable drivers,electromechanical drivers, etc., can be substituted for the lancetdriver 689 shown.

[0340] In one embodiment a pierceable membrane 692 is present betweenthe lancet tip 687 and the sample input port 682, sealing the lancet 686from any outside contact prior to use. A second membrane 693 may bepresent adjacent to the lancet head 688 sealing -the driver port 690.The pierceable membrane 692 and the second membrane 693 function toisolate the lancet 686 within the lancet chamber to maintain sterilityof the lancet 686 prior to use. During use the lancet tip 687 and theexternal lancet driver 691 pierce the pierceable membrane 692 and thesecond membrane 693, if present respectively.

[0341] A sample flow channel 695 leads from the sample input port 682 toan analytical region 696. The analytical region 696 is associated with asample sensor capable of being read by the analyzer device. If thesample sensor is optical in nature, the sample sensor may includeoptically transparent windows 697 in the housing above and below theanalytical region 696, allowing a light source in the analyzer device topass light 698 through the analytical region. An optical sensor 698′,e.g. a CMOS array, is present in the analyzer device for sensing thelight 699 that has passed through the analytical region 696 andgenerating a signal to be analyzed by the analyzer device.

[0342] In a separate embodiment, only one optically transparent windowis present, and the opposing side of the analytical region is silveredor otherwise reflectively coated to reflect light back through theanalytical region and-out-the window to be analyzed by the analyzerdevice. In an alternate embodiment, the sensor is electrochemical 700,e.g. an enzyme electrode, and includes a means of transmitting anelectric current from the sampling module cartridge to the analyzerdevice, e.g. an electrical contact 701, or plurality of electricalcontacts 701, on the housing accessible to the analyzer device.

[0343] In one embodiment, the pierceable membrane 692 may be made ofpolymer-based film that has been coated with a silicone-based gel. Forexample, the membrane structure may comprise a polymer-based filmcomposed of polyethylene terephthalate, such as the film sold under thetrademark MYLAR®. The membrane structure may further comprise a thincoating of a silicone-based gel such as the gel sold under the trademarkSYLGARD® on at least one surface of the film.

[0344] The usefulness of such a film is its ability to reseal after thelancet tip has penetrated it without physically affecting the lancet'scutting tip and edges. The MYLAR® film provides structural stabilitywhile the thin SYLGARD® silicone laminate is flexible enough to retainits form and close over the hole made in the MYLAR® film. Other similarmaterials fulfilling the structural stability and flexibility roles maybe used in the manufacture of the pierceable membrane in thisembodiment.

[0345] The pierceable membrane 692 operates to allow the lancet tip 687to pierce the pierceable membrane 692 as the lancet tip 687 travels intoand through the sampling port 682. In the described embodiment, thesilicone-based gel of the membrane 692 automatically seals the cutcaused by the lancet tip 687. Therefore, after an incision is made on afinger of a user and the lancet tip 687 is retracted back through thepierceable membrane 692, the blood from the incision is prevented fromflowing through the pierceable membrane 692, which aids the blood totravel through the sample flow channel 695 to accumulate within theanalytical region 696.

[0346] Thus the pierceable membrane 692 prevents blood, from flowinginto the lancet device assembly, and blood contamination and loss intothe lancet device mechanism cavity are prevented. In yet anotherembodiment, used sample input ports are automatically sealed off beforegoing to the next sample acquisition cycle by a simple button mechanism.A similar mechanism seals off a sample input port should sampling beunsuccessful.

[0347] In an alternate embodiment, a calibrant supply reservoir 702 isalso present in each sampling module. The calibrant supply reservoir 702is filled with a calibrant solution and is in fluid communication with acalibration chamber 703. The calibration chamber 703 provides a sourceof a known signal from the sampling module cartridge to be used tovalidate and quantify the test conducted in the analytical region 696.As such, the configuration of the calibration chamber 703 closelyresembles the analytical region 696.

[0348] During use, the calibrant solution is forced from the calibrantsupply reservoir 702 into the calibration chamber 703. The figuredepicts a stylized plunger 704 above the calibrant supply reservoir 702ready to squeeze the calibrant supply reservoir 702. In practice, avariety of methods of transporting small quantities of fluid are knownin the art and can be implemented on the sampling module cartridge. Thecalibration chamber 703 is associated with a calibrant testing means.

[0349]FIG. 73 shows two alternate calibrant testing means—opticalwindows 697 and an electrochemical sensor 676. In cases where thesampling module is designed to perform several different tests on theblood, both optical and electrochemical testing means may be present.The optical windows 697 allow passage of light 677 from the analyzerdevice through the calibration chamber 703, whereupon the light 703′leaving the calibration chamber 703 passes onto an optical sensor 698′to result in a signal in the analyzer device.

[0350] The electrochemical sensor 676 is capable of generating a signalthat is communicated to the analyzer device via, e g. an electricalcontact 704′, which is accessible to a contact probe 702′ on theanalyzer device that can be extended to contact the electrical contact704′. The calibrant solution may be any solution, which, in combinationwith the calibrant testing means, will provide a suitable signal, whichwill serve as calibration measurement to the analyzer device. Suitablecalibrant solutions are known in the art, e.g. glucose solutions ofknown concentration. The calibration measurement is used to adjust theresults obtained from sample sensor from the analytical region 696.

[0351] To maintain small size in some sampling module cartridgeembodiments, allowing small quantities of sampled blood to besufficient, each component of the sampling module must be small,particularly the sample flow channel and the analytical region. Thesample flow channel can be less than about 0.5 mm in diameter,specifically less than about 0.3 mm in diameter, more specifically lessthan about 0.2 mm in diameter, and even more specifically less thanabout 0.1 mm in diameter.

[0352] The sample flow channel may generally be at least about 50micrometers in diameter. The dimensions of the analytical region may beless than about 1 mm by about 1 mm by about 1 mm, specifically less thanabout 0.6 mm by about 0.6 mm by about 0.4 mm, more specifically lessthan about 0.4 mm by 0.4 mm by 0.2 mm, and even more specifically lessthan about 0.2 mm by about 0.2 mm by about 0.1 mm. The analytical regioncan generally be at least about 100 micrometers by 100 micrometers by 50micrometers.

[0353] The sampling module cartridge is able to return a valid testingresult with less than about 5 microliters of blood taken from the skinof a patient, specifically less than about 1 microliter, morespecifically less than about 0.4 microliters, and even more specificallyless than about 0.2 microliters. Generally, at least 0.05 microliters ofblood is drawn for a sample.

[0354] The cartridge housing may be made in a plurality of distinctpieces, which are then assembled to provide the completed housing. Thedistinct pieces may be manufactured from a wide range of substratematerials. Suitable materials for forming the described apparatusinclude, but are not limited to, polymeric materials, ceramics(including aluminum oxide and the like), glass, metals, composites, andlaminates thereof. Polymeric materials are particularly preferred hereinand will typically be organic polymers that are homopolymers orcopolymers, naturally occurring or synthetic, crosslinked oruncrosslinked.

[0355] It is contemplated that the various components and devicesdescribed herein, such as sampling module cartridges, sampling modules,housings, etc., may be made from a variety of materials, includingmaterials such as the following: polycarbonates; polyesters, includingpoly (ethylene terephthalate) and poly(butylene terephthalate);polyamides, (such as nylons); polyethers, including polyformaldehyde andpoly (phenylene sulfide); polyimides, such as that manufactured underthe trademarks KAPTON (DuPont, Wilmington, Del.) and UPILEX (UbeIndustries, Ltd., Japan); polyolefin compounds, including ABS polymers,Kel-F copolymers, poly(methyl methacrylate), poly(styrene-butadiene)copolymers, poly(tetrafluoroethylene), poly(ethylenevinyl acetate)copolymers, poly(N-vinylcarbazole) and polystyrene.

[0356] The various components and devices described herein may also befabricated from a “composite,” i.e., a composition comprised of unlikematerials. The composite may be a block composite, e.g., an A═B═A blockcomposite, an A═B═C block composite, or the like. Alternatively, thecomposite may be a heterogeneous combination of materials, i.e., inwhich the materials are distinct from separate phases, or a homogeneouscombination of unlike materials. A laminate composite with severaldifferent bonded layers of identical or different materials can also beused.

[0357] Other preferred composite substrates include polymer laminates,polymer-metal laminates, e.g., polymer coated with copper, aceramic-in-metal or a polymer-in-metal composite. One composite materialis a polyimide laminate formed from a first layer of polyimide such asKAPTON polyimide, available from DuPont (Wilmington, Del.), that hasbeen co-extruded with a second, thin layer of a thermal adhesive form ofpolyimide known as KJ®, also available from DuPont (Wilmington, Del.).

[0358] Any suitable fabrication method for the various components anddevices described herein can be used, including, but not limited to,molding and casting techniques, embossing methods, surface machiningtechniques, bulk machining techniques, and stamping methods. Further,injection-molding techniques well known in the art may be useful inshaping the materials used to produce sample modules and othercomponents.

[0359] For some embodiments, the first time a new sampling modulecartridge 668 is used, the user removes any outer packaging materialfrom the sampling module cartridge 668 and opens the lid 671 of theanalyzer device 669, exposing the chamber. The sampling module cartridge668 is slipped into the chamber and the lid 671 closed. The patient'sskin is positioned upon the sampling site 678 and the integrated processof lancing the skin, collecting the blood sample, and testing the bloodsample is initiated, e.g. by pressing a function button 674 to cause thelancet driver to be triggered. The patient's skin is maintained inposition upon the sampling site 678, adjacent the sample input port 682,until an adequate volume of blood has been collected, whereupon thesystem may emit a signal (e.g. an audible beep) that the patient's skinmay be lifted from the sampling site 678.

[0360] When the testing of the sample is complete, the analyzer device669 automatically reads the results from the sampling module cartridge668 and reports the results on the readout display 673. The analyzerdevice 669 may also store the result in memory for later downloading toa computer system. The sampling module cartridge 668 may thenautomatically be advanced to bring the next sampling module inline forthe next use. Each successive time the system is used (optionally untilthe sampling module cartridge 668 is used up), the patient's skin may beplaced upon the sampling site 678 of the (already installed) samplingmodule cartridge 668, thus simplifying the process of blood sampling andtesting.

[0361] A method of providing more convenient blood sampling, wherein aseries of blood samples may be collected and tested using a singledisposable sampling module cartridge which is designed to couple to ananalyzer device is described. Embodiments of the sampling modulecartridge include a plurality of sampling modules. Each sampling modulecan be adapted to perform a single blood sampling cycle and isfunctionally arranged within the sampling module cartridge to allow anew sampling module to be brought online after a blood sampling cycle iscompleted.

[0362] Each blood sampling cycle may include lancing of a patient'sskin, collection of a blood sample, and testing of the blood sample. Theblood sampling cycle may also include reading of information about theblood sample by the analyzer device, display and/or storage of testresults by the analyzer device, and/or automatically advancing thesampling module cartridge to bring a new sampling module online andready for the next blood sampling cycle to begin.

[0363] A method embodiment starts with coupling of the sampling modulecartridge and analyzer device and then initiating a blood samplingcycle. Upon completion of the blood sampling cycle, the sampling modulecartridge is advanced to bring a fresh, unused sampling module online,ready to perform another blood sampling cycle. Generally, at least tensampling modules are present, allowing the sampling module cartridge tobe advanced nine times after the initial blood sampling cycle.

[0364] In some embodiments, more sampling modules are present and thesampling module cartridge may be advanced about 19 times, and about 34times in some embodiments, allowing about 19 or about 34 blood samplingcycles, respectively, after the initial blood sampling cycle. After aseries of blood sampling cycles has been performed and substantially all(i.e. more than about 80%) of the sampling modules have been used, thesampling module cartridge is decoupled from the analyzer device anddiscarded, leaving the analyzer device ready to be coupled with a newsampling module cartridge.

[0365] Referring to FIGS. 74-76, a tissue penetration sampling device180 is shown with the controllable driver 179 of FIG. 20 coupled to asampling module cartridge 705 and disposed within a driver housing 706.A ratchet drive mechanism 707 is secured to the driver housing 706,coupled to the sampling module cartridge 705 and configured to advance asampling module belt 708 within the sampling module cartridge 705 so asto allow sequential use of each sampling module 709 in the samplingmodule belt 708. The ratchet drive mechanism 707 has a drive wheel 711configured to engage the sampling modules 709 of the sampling modulebelt 708. The drive wheel 711 is coupled to an actuation lever 712 thatadvances the drive wheel 711 in increments of the width of a singlesampling module 709. A T-slot drive coupler 713 is secured to theelongated coupler shaft 184.

[0366] A sampling module 709 is loaded and ready for use with the drivehead 198 of the lancet 183 of the sampling module 709 loaded in theT-slot 714 of the drive coupler 713. A sampling site 715 is disposed atthe distal end 716 of the sampling module 709 disposed about a lancetexit port 717. The distal end 716 of the sampling module 709 is exposedin a module window 718, which is an opening in a cartridge cover 721 ofthe sampling module cartridge 705. This allows the distal end 716 of thesampling module 709 loaded for use to be exposed to avoid contaminationof the cartridge cover 721 with blood from the lancing process.

[0367] A reader module 722 is disposed over a distal portion of thesampling module 709 that is loaded in the drive coupler 713 for use andhas two contact brushes 724 that are configured to align and makeelectrical contact with sensor contacts 725 of the sampling module 709as shown in FIG. 77. With electrical contact between the sensor contacts725 and contact brushes 724, the processor 193 of the controllabledriver 179 can read a signal from an analytical region 726 of thesampling module 709 after a lancing cycle is complete and a blood sampleenters the analytical region 726 of the sampling module 709. The contactbrushes 724 can have any suitable configuration that will allow thesampling module belt 708 to pass laterally beneath the contact brushes724 and reliably make electrical contact with the sampling module 709loaded in the drive coupler 713 and ready for use. A spring loadedconductive ball bearing is one example of a contact brush 724 that couldbe used. A resilient conductive strip shaped to press against the insidesurface of the flexible polymer sheet 727 along the sensor contactregion 728 of the sampling module 709 is another embodiment of a contactbrush 724.

[0368] The sampling module cartridge 705 has a supply canister 729 and areceptacle canister 730. The unused sampling modules of the samplingmodule belt 708 are disposed within the supply canister 729 and thesampling modules of the sampling module belt 708 that have been used areadvanced serially after use into the receptacle canister 730.

[0369]FIG. 77 is a perspective view of a section of the sampling modulebelt 708 shown in the sampling module cartridge 705 in FIG. 74. Thesampling module belt 708 has a plurality of sampling modules 709connected in series by a sheet of flexible polymer 727. The samplingmodule belt 708 shown in FIG. 77 is formed from a plurality of samplingmodule body portions 731 that are disposed laterally adjacent each otherand connected and sealed by a single sheet of flexible polymer 727. Theflexible polymer sheet 727 can optionally have sensor contacts 725,flexible electrical conductors 732, sample sensors 733 or anycombination of these elements formed on the inside surface 734 of theflexible polymer sheet 727. These electrical, optical or chemicalelements can be formed by a variety of methods including vapordeposition and the like.

[0370] The proximal portion 735 of the flexible polymer sheet 727 hasbeen folded over on itself in order to expose the sensor contacts 725 tothe outside surface of the sampling module 709. This makes electricalcontact between the contact brushes 724 of the reader module 722 and thesensor contacts 725 easier to establish as the sampling modules 709 areadvanced and loaded into position with the drive coupler 713 of thecontrollable driver 179 ready for use. The flexible polymer sheet 727can be secured to the sampling module body portion 731 by adhesivebonding, solvent bonding, ultrasonic thermal bonding or any othersuitable method.

[0371]FIG. 78 shows a perspective view of a single sampling module 709of the sampling module belt 708 of FIG. 77 during the assembly phase ofthe sampling module 709. The proximal portion 735 of the flexiblepolymer sheet 727 is being folded over on itself as shown in order toexpose the sensor contacts 725 on the inside surface of the flexiblepolymer sheet 727. FIG. 79 is a bottom view of a section of the flexiblepolymer sheet 727 of the sampling module 709 of FIG. 78 illustrating thesensor contacts 725, flexible conductors 732 and sample sensors 733deposited on the bottom surface of the flexible polymer sheet 727.

[0372] A lancet 183 is shown disposed within the lancet channel 736 ofthe sampling module 709 of FIG. 78 as well as within the lancet channels736 of the sampling modules 709 of the sampling module belt 708 of FIG.77. The lancet 183 has a tip 196 and a shaft portion 201 and a drivehead 198. The shaft portion 201 of the lancet slides within the lancetchannel 736 of the sampling module 709 and the drive head 198 of thelancet 183 has clearance to move in a proximal and distal directionwithin the drive head slot 737 of the sampling module 709. Disposedadjacent the drive head slot 737 and at least partially forming thedrive head slot are a first protective strut 737′ and a secondprotective strut 737″ that are elongated and extend substantiallyparallel to the lancet 183.

[0373] In one lancet 183 embodiment, the drive head 198 of the lancet183 can have a width of about 0.9 to about 1.1 mm. The thickness of thedrive head 198 of the lancet 183 can be about 0.4 to about 0.6 mm. Thedrive head slot 714 of the sampling module 709 should have a width thatallows the drive head 198 to move freely within the drive head slot 714.The shaft portion 201 of the lancet 183 can have a transverse dimensionof about 50 mm to about 1000 mm. Typically, the shaft portion 201 of thelancet 183 has a round transverse cross section, however, otherconfigurations are contemplated.

[0374] The sampling module body portions 731 and the sheet of flexiblepolymer 727 can both be made of polymethylmethacrylate (PMMA), or anyother suitable polymer, such as those discussed above. The dimensions ofa typical sampling module body portion 731 can be about 14 to about 18mm in length, about 4 to about 5 mm in width, and about 1.5 to about 2.5mm in thickness. In other embodiments, the length of the sample modulebody portion can be about 0.5 to about 2.0 inch and the transversedimension can be about 0.1 to about 0.5 inch. The thickness of theflexible polymer sheet 727 can be about 100 to about 150 microns. Thedistance between adjacent sampling modules 709 in the sampling modulebelt 708 can vary from about 0.1 mm to about 0.3 mm, and in someembodiments, from about 0.2 to about 0.6.

[0375]FIGS. 80 and 81 show a perspective view of the body portion 731 ofthe sampling module 709 of FIG. 77 without the flexible polymer coversheet 727 or lancet 183 shown for purposes of illustration. FIG. 81 isan enlarged view of a portion of the body portion 731 of the samplingmodule 709 of FIG. 80 illustrating the sampling site 715, sample inputcavity 715′, sample input port 741, sample flow channel 742, analyticalregion 743, control chamber 744, vent 762, lancet channel 736, lancetchannel stopping structures 747 and 748 and lancet guides 749-751 of thesampling module 709.

[0376] The lancet channel 736 has a proximal end 752 and a distal end753 and includes a series of lancet bearing guide portions 749-751 andsample flow stopping structures 747-748. The lancet guides 749-751 maybe configured to fit closely with the shaft of the lancet 183 andconfine the lancet 183 to substantially axial movement. At the distalend 753 of the lancet channel 736 the distal-most lancet guide portion749 is disposed adjacent the sample input port 741 and includes at itsdistal-most extremity, the lancet exit port 754 which is disposedadjacent the sample input cavity 715′. The sample input cavity can havea transverse dimension, depth or both, of about 2 to 5 times thetransverse dimension of the lancet 183, or about 0.2 to about 2 mm,specifically, about 0.4 to about 1.5 mm, and more specifically, about0.5 to about 1.0 mm. The distal-most lancet guide 749 can have innertransverse dimensions of about 300 to about 350 microns in width andabout 300 to about 350 microns in depth. Proximal of the distal-mostlancet guide portion 749 is a distal sample flow stop 747 that includesa chamber adjacent the distal-most lancet 749. The chamber has atransverse dimension that is significantly larger than the transversedimension of the distal-most lancet guide 749. The chamber can have awidth of about 600 to about 800 microns, and a depth of about 400 toabout 600 microns and a length of about 2000 to about 2200 microns. Therapid transition of transverse dimension and cross sectional areabetween the distal-most lancet bearing guide 749 and the distal sampleflow stop 747 interrupts the capillary action that draws a fluid samplethrough the sample input cavity 715′ and into the lancet channel 736.

[0377] A center lancet bearing guide 750 is disposed proximal of thedistal lancet channel stop 747 and can have dimensions similar to thoseof the distal-most lancet bearing guide 749. Proximal of the centerlancet guide 750 is a proximal lancet channel stop 748 with a chamber.The dimensions of the proximal lancet channel stop can be the same orsimilar to those of the distal lancet channel stop 747. The proximallancet channel stop 748 can have a width of about 600 to about 800microns, and a depth of about 400 to about 600 microns and a length ofabout 2800 to about 3000 microns. Proximal of the proximal lancetchannel stop 748 is a proximal lancet guide 751. The proximal lancetguide 751 can dimensions similar to those of the other lancet guide 749and 750 portions with inner transverse dimensions of about 300 to about350 microns in width and about 300 to about 350 microns in depth.Typically, the transverse dimension of the lancet guides 749-751 areabout 10 percent larger than the transverse dimension of the shaftportion 201 of the lancet 183 that the lancet guides 749-751 areconfigured to guide.

[0378] A proximal fracturable seal (not shown) can be positioned betweenthe proximal lancet guide 751 and the shaft portion 201 of the lancet183 that seals the chamber of the proximal lancet channel stop 748 fromthe outside environment. The fracturable seal seals the chamber of theproximal lancet channel stop 748 and other interior portions of thesample chamber from the outside environment when the sampling module 709is stored for use. The fracturable seal remains intact until the lancet183 is driven distally during a lancet cycle at which point the seal isbroken and the sterile interior portion of the sample chamber is exposedand ready to accept input of a liquid sample, such as a sample of blood.A distal fracturable seal (not shown) can be disposed between the lancet183 and the distal-most lancet guide 749 of the sampling module 709 toseal the distal end 753 of the lancet channel 736 and sample input port741 to maintain sterility of the interior portion of the sampling module709 until the lancet 183 is driven forward during a lancing cycle.

[0379] Adjacent the lancet exit port 754 within the sample input cavity715′ is the sample input port 741 that is configured to accept a fluidsample that emanates into the sample input cavity 715′ from targettissue 233 at a lancing site after a lancing cycle. The dimensions ofthe sample input port 741 can a depth of about 60 to about 70 microns, awidth of about 400 to about 600 microns. The sample input cavity canhave a transverse dimension of about 2 to about 5 times the transversedimension of the lancet 183, or about 400 to about 1000 microns. Thesample input cavity serves to accept a fluid sample as it emanates fromlanced tissue and direct the fluid sample to the sample input port 741and thereafter the sample flow channel 742. The sample flow channel 742is disposed between and in fluid communication with the sample inputport 741 and the analytical region 743. The transverse dimensions of thesample flow channel 742 can be the same as the transverse dimensions ofthe sample input port 741 with a depth of about 60 to about 70 microns,a width of about 400 to about 600 microns. The length of the sample flowchannel 742 can be about 900 to about 1100 microns. Thus, in use, targettissue is disposed on the sampling site 715 and a lancing cycleinitiated. Once the target tissue 233 has been lanced and the samplebegins to flow therefrom, the sample enters the sample input cavity 715′and then the sample input port 741. The sample input cavity 715′ may besized and configured to facilitate sampling success by applying pressureto a perimeter of target tissue 233 before, during and after the lancingcycle and hold the wound track open after the lancing cycle to allowblood or other fluid to flow from the wound track and into the sampleinput cavity 715′. From the sample input port 741, the sample in thendrawn by capillary or other forces through the sample flow channel 742and into the analytical region 743 and ultimately into the controlchamber 744. The control chamber 744 may be used to provide indirectconfirmation of a complete fill of the analytical region 743 by a samplefluid. If a fluid sample has been detected in the control chamber 744,this confirms that the sample has completely filled the analyticalregion 743. Thus, sample detectors may be positioned within the controlchamber 744 to confirm filling of the analytical region 743.

[0380] The analytical region 743 is disposed between and in fluidcommunication with the sample flow channel 742 and the control chamber744. The analytical region 743 can have a depth of about 60 to about 70microns, a width of about 900 to about 1100 microns and a length ofabout 5 to about 6 mm. A typical volume for the analytical region 743can be about 380 to about 400 nanoliters. The control chamber 744 isdisposed adjacent to and proximal of the analytical region 743 and canhave a transverse dimension or diameter of about 900 to about 1100microns and a depth of about 60 to about 70 microns.

[0381] The control chamber 744 is vented to the chamber of the proximallancet channel stop 748 by a vent that is disposed between and in fluidcommunication with the control chamber 744 and the chamber of theproximal lancet channel stop 748. Vent 762 can have transversedimensions that are the same or similar to those of the sample flowchannel 742 disposed between the analytical region 743 and the sampleinput port 741. Any of the interior surfaces of the sample input port741, sample flow channels 742 and 762, analytical region 743, vents 745or control chamber 744 can be coated with a coating that promotescapillary action. A hydrophilic coating such as a detergent is anexample of such a coating.

[0382] The analytical region 743 accommodates a blood sample thattravels by capillary action from the sampling site 715 through thesample input cavity 715′ and into the sample input port 741, through thesample flow channel 742 and into the analytical region 743. The bloodcan then travel into the control chamber 744. The control chamber 744and analytical region 743 are both vented by the vent 762 that allowsgases to escape and prevents bubble formation and entrapment of a samplein the analytical region 743 and control chamber 744. Note that, inaddition to capillary action, flow of a blood sample into the analyticalregion 743 can be facilitated or accomplished by application of vacuum,mechanical pumping or any other suitable method.

[0383] Once a blood sample is disposed within the analytical region 743,analytical testing can be performed on the sample with the resultstransmitted to the processor 193 by electrical conductors 732, opticallyor by any other suitable method or means. In some embodiments, it may bedesirable to confirm that the blood sample has filled the analyticalregion 743 and that an appropriate amount of sample is present in thechamber in order to carry out the analysis on the sample.

[0384] Confirmation of sample arrival in either the analytical region743 or the control chamber 744 can be achieved visually, through theflexible polymer sheet 727 which can be transparent. However, it may bedesirable in some embodiments to use a very small amount of blood samplein order to reduce the pain and discomfort to the patient during thelancing cycle. For sampling module 709 embodiments such as describedhere, having the sample input cavity 715′ and sample input port 741adjacent the lancet exit port 754 allows the blood sample to becollected from the patient's skin 233 without the need for moving thesampling module 709 between the lancing cycle and the sample collectionprocess. As such, the user does not need to be able to see the sample inorder to have it transferred into the sampling module 709. Because ofthis, the position of the sample input cavity 715′ and the sample inputport 741 adjacent the lancet exit port 754 allows a very small amount ofsample to be reliably obtained and tested.

[0385] Samples on the order of tens of nanoliters, such as about 10 toabout 50 nanoliters can be reliably collected and tested with a samplingmodule 709. This size of blood sample is too small to see and reliablyverify visually. Therefore, it is necessary to have another method toconfirm the presence of the blood sample in the analytical region 743.Sample sensors 733, such as the thermal sample sensors discussed abovecan positioned in the analytical region 743 or control chamber 744 toconfirm the arrival of an appropriate amount of blood sample.

[0386] In addition, optical methods, such as spectroscopic analysis ofthe contents of the analytical region 743 or control chamber 744 couldbe used to confirm arrival of the blood sample. Other methods such aselectrical detection could also be used and these same detection methodscan also be disposed anywhere along the sample flow path through thesampling module 709 to confirm the position or progress of the sample(or samples) as it moves along the flow path as indicated by the arrows763 in FIG. 81. The detection methods described above can also be usefulfor analytical methods requiring an accurate start time.

[0387] The requirement for having an accurate start time for ananalytical method can in turn require rapid filling of an analyticalregion 743 because many analytical processes begin once the blood sampleenters the analytical region 743. If the analytical region 743 takes toolong to fill, the portion of the blood sample that first enters theanalytical region 743 will have been tested for a longer time that thelast portion of the sample to enter the analytical region 743 which canresult in inaccurate results. Therefore, it may be desirable in thesecircumstances to have the blood sample flow first to a reservoir,filling the reservoir, and then have the sample rapidly flow all at oncefrom the reservoir into the analytical region 743.

[0388] In one embodiment of the sampling module 709, the analyticalregion 743 can have a transverse cross section that is substantiallygreater than a transverse cross section of the control chamber 744. Thechange in transverse cross section can be accomplished by restrictionsin the lateral transverse dimension of the control chamber 744 versusthe analytical region 743, by step decreases in the depth of the controlchamber 744, or any other suitable method. Such a step between theanalytical region 743 and the control chamber 744 is shown in FIG. 81.In such an embodiment, the analytical region 743 can behave as a samplereservoir and the control chamber 744 as an analytical region thatrequires rapid or nearly instantaneous filling in order to have aconsistent analysis start time. The analytical region 743 fills by aflow of sample from the sample flow channel 742 until the analyticalregion is full and the sample reaches the step decrease in chamber depthat the boundary with the control chamber 744. Once the sample reachesthe step decrease in cross sectional area of the control chamber 744,the sample then rapidly fills the control chamber 744 by virtue of theenhanced capillary action of the reduced cross sectional area of thecontrol chamber 744. The rapid filling of the control chamber allows anyanalytical process initiated by the presence of sample to be carried outin the control chamber 744 with a reliable start time for the analyticalprocess for the entire sample of the control chamber 744.

[0389] Filling by capillary force is passive. It can also be useful forsome types of analytical testing to discard the first portion of asample that enters the sampling module 709, such as the case where theremay be interstitial fluid contamination of the first portion of thesample. Such a contaminated portion of a sample can be discarded byhaving a blind channel or reservoir that draws the sample by capillaryaction into a side sample flow channel (not shown) until the side sampleflow channel or reservoir in fluid communication therewith, is full. Theremainder of the sample can then proceed to a sample flow channeladjacent the blind sample flow channel to the analytical region 743.

[0390] For some types of analytical testing, it may be advantageous tohave multiple analytical regions 743 in a single sampling module 709. Inthis way multiple iterations of the same type of analysis could beperformed in order to derive some statistical information, e.g.averages, variation or confirmation of a given test or multiple testsmeasuring various different parameters could be performed in differentanalytical regions 743 in the same sampling module 709 filled with ablood sample from a single lancing cycle.

[0391]FIG. 82 is an enlarged elevational view of a portion of analternative embodiment of a sampling module 766 having a plurality ofsmall volume analytical regions 767. The small volume analytical regions767 can have dimensions of about 40 to about 60 microns in width in bothdirections and a depth that yields a volume for each analytical region767 of about 1 nanoliter to about 100 nanoliters, specifically about 10nanoliters to about 50 nanoliters. The array of small volume analyticalregions 767 can be filled by capillary action through a sample flowchannel 768 that branches at a first branch point 769, a second branchpoint 770 and a third branch point 771. Each small volume analyticalregion 767 can be used to perform a like analytical test or a variety ofdifferent tests can be performed in the various analytical regions 767.

[0392] For some analytical tests, the analytical regions 767 must havemaintain a very accurate volume, as some of the analytical tests thatcan be performed on a blood sample are volume dependent. Some analyticaltesting methods detect glucose levels by measuring the rate or kineticof glucose consumption. Blood volume required for these tests is on theorder of about I to about 3 microliters. The kinetic analysis is notsensitive to variations in the volume of the blood sample as it dependson the concentration of glucose in the relatively large volume samplewith the concentration of glucose remaining essentially constantthroughout the analysis. Because this type of analysis dynamicallyconsumes glucose during the testing, it is not suitable for use withsmall samples, e.g. samples on the order of tens of nanoliters where theconsumption of glucose would alter the concentration of glucose.

[0393] Another analytical method uses coulomb metric measurement ofglucose concentration. This method is accurate if the sample volume isless than about 1 microliter and the volume of the analytical region isprecisely controlled. The accuracy and the speed of the method isdependent on the small and precisely known volume of the analyticalregion 767 because the rate of the analysis is volume dependent andlarge volumes slow the reaction time and negatively impact the accuracyof the measurement.

[0394] Another analytical method uses an optical fluorescence decaymeasurement that allows very small sample volumes to be analyzed. Thismethod also requires that the volume of the analytical region 767 beprecisely controlled. The small volume analytical regions 767 discussedabove can meet the criteria of maintaining small accurately controlledvolumes when the small volume analytical regions 767 are formed usingprecision manufacturing techniques. Accurately formed small volumeanalytical regions 767 can be formed in materials such as PMMA bymethods such as molding and stamping. Machining and etching, either bychemical or laser processes can also be used. Vapor deposition andlithography can also be used to achieve the desired results.

[0395] The sampling modules 709 and 766 discussed above all are directedto embodiments that both house the lancet 183 and have the ability tocollect and analyze a sample. In some embodiments of a sampling module,the lancet 183 may be housed and a sample collected in a samplereservoir without any analytical function. In such an embodiment, theanalysis of the sample in the sample reservoir may be carried out bytransferring the sample from the reservoir to a separate analyzer. Inaddition, some modules only serve to house a lancet 183 without anysample acquisition capability at all. The body portion 774 of such alancet module 775 is shown in FIG. 83. The lancet module 775 has anouter structure similar to that of the sampling modules 709 and 766discussed above, and can be made from the same or similar materials.

[0396] A flexible polymer sheet 727 (not shown) can be used to cover theface of the lancet module 775 and contain the lancet 183 in a lancetchannel 776 that extends longitudinally in the lancet module bodyportion 774. The flexible sheet of polymer 727 can be from the samematerial and have the same dimensions as the flexible polymer sheet 727discussed above. Note that the proximal portion of the flexible polymersheet 727 need not be folded over on itself because there are no sensorcontacts 725 to expose. The flexible polymer sheet 727 in such a lancetmodule 775 serves only to confine the lancet 183 in the lancet channel776. The lancet module 775 can be configured in a lancet module belt,similar to the sampling module belt 708 discussed above with theflexible polymer sheet 727 acting as the belt. A drive head slot 777 isdispose proximal of the lancet channel 776.

[0397] With regard to the tissue penetration sampling device 180 of FIG.74, use of the device 180 begins with the loading of a sampling modulecartridge 705 into the controllable driver housing 706 so as to couplethe cartridge 705 to the controllable driver housing 706 and engage thesampling module belt 708 with the ratchet drive 707 and drive coupler713 of the controllable driver 179. The drive coupler 713 can have aT-slot configuration such as shown in FIGS. 84 and 85. The distal end ofthe elongate coupler shaft 184 is secured to the drive coupler 713 whichhas a main body portion 779, a first and second guide ramp 780 and 781and a T-slot 714 disposed within the main body portion 779. The T-slot714 is configured to accept the drive head 198 of the lancet 183. Afterthe sampling module cartridge 705 is loaded into the controllable driverhousing 706, the sampling module belt 708 is advanced laterally untilthe drive head 198 of a lancet 183 of one of the sampling modules 709 isfed into the drive coupler 713 as shown in FIGS. 86-88. FIGS. 86-88 alsoillustrate a lancet crimp device 783 that bends the shaft portion 201 ofa used lancet 183 that is adjacent to the drive coupler 713. Thisprevents the used lancet 183 from moving out through the module body 731and being reused.

[0398] As the sampling modules 709 of the sampling module belt 708 areused sequentially, they are advanced laterally one at a time into thereceptacle canister 730 where they are stored until the entire samplingmodule belt 708 is consumed. The receptacle canister 730 can then beproperly disposed of in accordance with proper techniques for disposalof blood-contaminated waste. The sampling module cartridge 705 allowsthe user to perform multiple testing operations conveniently withoutbeing unnecessarily exposed to blood waste products and need onlydispose of one cartridge after many uses instead of having to dispose ofa contaminated lancet 183 or module 709 after each use.

[0399]FIGS. 89 and 90 illustrate alternative embodiments of samplingmodule cartridges. FIG. 89 shows a sampling module cartridge 784 in acarousel configuration with adjacent sampling modules 785 connectedrigidly and with sensor contacts 786 from the analytical regions of thevarious sampling modules 785 disposed near an inner radius 787 of thecarousel. The sampling modules 785 of the sampling module cartridge 784are advanced through a drive coupler 713 but in a circular as opposed toa linear fashion.

[0400]FIG. 90 illustrates a block of sampling modules 788 in a four byeight matrix. The drive head 198 of the lancets 183 of the samplingmodules 789 shown in FIG. 90 are engaged and driven using a differentmethod from that of the drive coupler 713 discussed above. The driveheads 198 of the lancets 183 have an adhesive coating 790 that mateswith and secures to the drive coupler 791 of the lancet driver 179,which can be any of the drivers, including controllable drivers,discussed above.

[0401] The distal end 792 of the drive coupler 791 contacts and sticksto the adhesive 790 of proximal surface of the drive head 198 of thelancet 183 during the beginning of the lancet cycle. The driver coupler791 pushes the lancet 183 into the target tissue 237 to a desired depthof penetration and stops. The drive coupler 791 then retracts the lancet183 from the tissue 233 using the adhesive contact between the proximalsurface of the drive head 198 of the lancet 183 and distal end surfaceof the drive coupler 791, which is shaped to mate with the proximalsurface.

[0402] At the top of the retraction stroke, a pair of hooked members 793which are secured to the sampling module 789 engage the proximal surfaceof the drive head 198 and prevent any further retrograde motion by thedrive head 198 and lancet 183. As a result, the drive coupler 791 breaksthe adhesive bond with the drive head 198 and can then be advanced by anindexing operation to the next sampling module 789 to be used.

[0403]FIG. 91 is a side view of an alternative embodiment of a drivecoupler 796 having a lateral slot 797 configured to accept the L-shapeddrive head 798 of the lancet 799 that is disposed within a lancet module800 and shown with the L-shaped drive head 798 loaded in the lateralslot 797. FIG. 92 is an exploded view of the drive coupler 796, lancet799 with L-shaped drive head 798 and lancet module 800 of FIG. 91. Thistype of drive coupler 796 and drive head 798 arrangements could besubstituted for the configuration discussed above with regard to FIGS.84-88. The L-shaped embodiment of the drive head 798 may be a lessexpensive option for producing a coupling arrangement that allows serialadvancement of a sampling module belt or lancet module belt through thedrive coupler 796 of a lancet driver, such as a controllable lancetdriver 179.

[0404] For some embodiments of multiple lancing devices 180, it may bedesirable to have a high capacity-lancing device that does not require alancet module 775 in order to house the lancets 183 stored in acartridge. Eliminating the lancet modules 775 from a multiple lancetdevice 180 allows for a higher capacity cartridge because the volume ofthe cartridge is not taken up with the bulk of multiple modules 775.FIGS. 93-96 illustrate a high capacity lancet cartridge coupled to abelt advance mechanism 804. The belt advance mechanism 804 is secured toa controlled driver 179 housing which contains a controlledelectromagnetic driver.

[0405] The lancet cartridge 803 has a supply canister 805 and areceptacle canister 806. A lancet belt 807 is disposed within the supplycanister 805. The lancet belt 807 contains multiple sterile lancets 183with the shaft portion 201 of the lancets 183 disposed between theadhesive surface 808 of a first carrier tape 809 and the adhesivesurface 810 of a second carrier tape 811 with the adhesive surfaces 808and 810 pressed together around the shaft portion 201 of the lancets 183to hold them securely in the lancet belt 807. The lancets 183 have driveheads 198 which are configured to be laterally engaged with a drivecoupler 713, which is secured to an elongate coupler shaft 184 of thecontrollable driver 179.

[0406] The belt advance mechanism 804 includes a first cog roller 814and a second cog roller 815 that have synchronized rotational motion andare advanced in unison in an incremental indexed motion. The indexedmotion of the first and second cog rollers 814 and 815 advances thelancet belt 807 in units of distance equal to the distance between thelancets 183 disposed in the lancet belt 807. The belt advance mechanism804 also includes a first take-up roller 816 and a second take-up roller817 that are configured to take up slack in the first and second carriertapes 809 and 811 respectively.

[0407] When a lancet belt cartridge 803 is loaded in the belt advancemechanism 804, a lead portion 818 of the first carrier tape 809 isdisposed between a first cog roller 814 and a second cog roller 815 ofthe belt advance mechanism 804. The lead portion 818 of the firstcarrier tape 809 wraps around the outer surface 819 of the first turningroller 827, and again engages roller 814 with the cogs 820 of the firstcog roller 814 engaged with mating holes 821 in the first carrier tape809. The lead portion 818 of the first carrier tape 809 is then securedto a first take-up roller 816. A lead portion 822 of the second carriertape 811 is also disposed between the first cog roller 814 and secondcog roller 815 and is wrapped around an outer surface 823 of the secondturning roller 828, and again engages roller 815 with the cogs 826′ ofthe second cog roller 815 engaged in with mating holes 825 of the secondcarrier tape 811. The lead portion 822 of the second carrier tape 811 isthereafter secured to a second take-up roller 817.

[0408] As the first and second cog rollers 814 and 815 are advanced, theturning rollers 827 and 828 peel the first and second carrier tapes 809and 811 apart and expose a lancet 183. The added length or slack of theportions of the first and second carrier tapes 809 and 811 produced fromthe advancement of the first and second cog rollers 814 and 815 is takenup by the first and second take-up rollers 816 and 817. As a lancet 183is peeled out of the first and second carrier tapes 809 and 811, theexposed lancet 183 is captured by a lancet guide wheel 826′ of the beltadvance mechanism 804, shown in FIG. 96, which is synchronized with thefirst and second cog rollers 814 and 815. The lancet guide wheel 826′then advances the lancet 183 laterally until the drive head 198 of thelancet 183 is loaded into the drive coupler 713 of the controllabledriver 179. The controllable driver 179 can then be activated drivingthe lancet 183 into the target tissue 233 and retracted to complete thelancing cycle.

[0409] Once the lancing cycle is complete, the belt advance mechanism804 can once again be activated which rotates the lancet guide wheel 826and advances the used lancet 183 laterally and into the receptaclecanister 806. At the same time, a new unused lancet 183 is loaded intothe drive coupler 713 and readied for the next lancing cycle. Thisrepeating sequential use of the multiple lancing device 180 continuesuntil all lancets 183 in the lancet belt 807 have been used and disposedof in the receptacle canister 806. After the last lancet 183 has beenconsumed, the lancet belt cartridge 803 can then be removed and disposedof without exposing the user to any blood contaminated materials. Thebelt advance mechanism 804 can be activated by a variety of methods,including a motorized drive or a manually operated thumbwheel which iscoupled to the first and second cog rollers 814 and 815 and lancet guidewheel 826.

[0410] Although discussion of the devices described herein has beendirected primarily to substantially painless methods and devices foraccess to capillary blood of a patient, there are many other uses forthe devices and methods. For example, the tissue penetration devicesdiscussed herein could be used for substantially painless delivery ofsmall amounts of drugs, or other bioactive agents such as gene therapyagents, vectors, radioactive sources etc. As such, it is contemplatedthat the tissue penetration devices and lancet devices discussed hereincould be used to delivery agents to positions within a patient's body aswell as taking materials from a patient's body such as blood, lymphfluid, spinal fluid and the like. Drugs delivered may include analgesicsthat would further reduce the pain perceived by the patient uponpenetration of the patient's body tissue, as well as anticoagulants thatmay facilitate the successful acquisition of a blood sample uponpenetration of the patient's tissue.

[0411] Referring to FIGS. 97-101, a device for injecting a drug or otheruseful material into the tissue of a patient is illustrated. The abilityto localize an injection or vaccine to a specific site within a tissue,layers of tissue or organ within the body can be important. For example,epithelial tumors can be treated by injection of antigens, cytokine, orcolony stimulating factor by hypodermic needle or high-pressureinjection sufficient for the antigen to enter at least the epidermis orthe dermis of a patient. Often, the efficacy of a drug or combinationdrug therapy depends on targeted delivery to localized areas thusaffecting treatment outcome.

[0412] The ability to accurately deliver drugs or vaccinations to aspecific depth within the skin or tissue layer may avoid wastage ofexpensive drug therapies therefore impacting cost effectiveness of aparticular treatment. In addition, the ability to deliver a drug orother agent to a precise depth can be a clear advantage where theoutcome of treatment depends on precise localized drug delivery (such aswith the treatment of intralesional immunotherapy). Also, rapidinsertion velocity of a hypodermic needle to a precise predetermineddepth in a patient's skin is expected to reduce pain of insertion of theneedle into the skin. Rapid insertion and penetration depth of ahypodermic needle, or any other suitable elongated delivery devicesuitable for penetrating tissue, can be accurately controlled by virtueof a position feedback loop of a controllable driver coupled to thehypodermic needle.

[0413]FIG. 97 illustrates 901 distal end 901 of a hypodermic needle 902being,driven into layers of skin tissue 903 by an electromagneticcontrollable driver 904. The electromagnetic controllable driver 904 ofFIG. 79 can have any suitable configuration, such as the configurationof electromagnetic controllable drivers discussed above. The layers ofskin 903 being penetrated include the stratum corneum 905, the stratumlucidum 906, the stratum granulosum 907, the stratum spinosum 908, thestratum basale 909 and the dermis 911. The thickness of the stratumcorneum 905 is typically about 300 micrometers in thickness. The portionof the epidermis excluding the stratum corneum 905 includes the stratumlucidum 906, stratum granulosum 907, and stratum basale can be about 200micrometers in thickness. The dermis can be about 1000 micrometers inthickness. In FIG. 97, an outlet port 912 of the hypodermic needle 902is shown disposed approximately in the stratum spinosum 908 layer of theskin 903 injecting an agent 913 into the stratum spinosum 908.

[0414] FIGS. 98-101 illustrate an agent injection module 915 includingan injection member 916, that includes a collapsible canister 917 andthe hypodermic needle 902, that may be driven or actuated by acontrollable driver, such as any of the controllable drivers, discussedabove, to drive the hypodermic needle into the skin 903 for injection ofdrugs, vaccines or the like. The agent injection module 915 has areservoir, which can be in the form of the collapsible canister 917having a main chamber 918, such as shown in FIG. 98, for the drug orvaccine 913 to be injected. A cassette of a plurality of agent injectionmodules 915 (not shown) may provide a series of metered doses forlong-term medication needs. Such a cassette may be configured similarlyto the module cassettes discussed above. Agent injection modules 915 andneedles 902 may be disposable, avoiding biohazard concerns from unspentdrug or used hypodermic needles 902. The geometry of the cutting facets921 of the hypodermic needle shown in FIG. 79, may be the same orsimilar to the geometry of the cutting facets of the lancet 183discussed above.

[0415] Inherent in the position and velocity control system of someembodiments of a controllable driver is the ability to preciselydetermine the position or penetration depth of the hypodermic needle 902relative to the controllable driver or layers of target tissue or skin903 being penetrated. For embodiments of controllable drivers that useoptical encoders for position sensors, such as an Agilent HEDS 9200series, and using a four edge detection algorithm, it is possible toachieve an in plane spatial resolution of ±17 μm in depth. If a totaltissue penetration stroke is about 3 mm in length, such as might be usedfor intradermal or subcutaneous injection, a total of 88 position pointscan be resolved along the penetration stroke. A spatial resolution thisfine allows precise placement of a distal tip 901 or outlet port 912 ofthe hypodermic needle 902 with respect to the layers of the skin 903during delivery of the agent or drug 913. In some embodiments, adisplacement accuracy of better than about 200 microns can be achieved,in others a displacement accuracy of better than about 40 microns can beachieved.

[0416] The agent injection module 915 includes the injection member 916which includes the hypodermic needle 902 and drug reservoir orcollapsible canister 917, which may couple to an elongated coupler shaft184 via a drive coupler 185 as shown. The hypodermic needle 902 can bedriven to a desired penetration depth, and then the drug or other agent913, such as a vaccine, is passed into an inlet port 922 of the needle902 through a central lumen 923 of the hypodermic needle 902 as shown byarrow 924, shown in FIG. 98, and out of the outlet port 912 at thedistal end 901 of the hypodermic needle 902, shown in FIG. 97.

[0417] Drug or agent delivery can occur at the point of maximumpenetration, or following retraction of the hypodermic needle 902. Insome embodiments, it may be desirable to deliver the drug or agent 913during insertion of the hypodermic needle 902. Drug or agent deliverycan continue as the hypodermic needle 902 is being withdrawn (this iscommonly the practice during anesthesia in dental work). Alternativelydrug delivery can occur while the needle 902 is stationary during anypart of the retraction phase.

[0418] The hollow hypodermic needle 902 is fitted with the collapsiblecanister 917 containing a drug or other agent 913 to be dispensed. Thewalls 928 of this collapsible canister 917 can be made of a softresilient material such as plastic, rubber, or any other suitablematerial. A distal plate 925 is disposed at the distal end 926 of thecollapsible canister is fixed securely to the shaft 927 of thehypodermic needle proximal of the distal tip 901 of the hypodermicneedle 902. The distal plate 925 is sealed and secured to the shaft 927of the hypodermic needle 902 to prevent leakage of the medication 913from the collapsible canister 917.

[0419] A proximal plate 931 disposed at a proximal end 932 of thecollapsible canister 917 is slidingly fitted to a proximal portion 933of the shaft 927 of the hypodermic needle 902 with a sliding seal 934.The sliding seal 934 prevents leakage of the agent or medication 913between the seal 934 and an outside surface of the shaft 927 of thehypodermic needle 902. The sliding seal allows the proximal plate 931 ofthe collapsible canister 917 to slide axially along the needle 902relative to the distal plate 925 of the collapsible canister 917. A drugdose may be loaded into the main chamber 918 of the collapsible canister917 during manufacture, and the entire assembly protected duringshipping and storage by packaging and guide fins 935 surrounding thedrive head slot 936 of the agent injection module 915.

[0420] An injection cycle may begin when the agent injection module 915is loaded into a ratchet advance mechanism (not shown), and registeredat a drive position with a drive head 937 of the hypodermic needle 902engaged in the drive coupler 185. The position of the hypodermic needle902 and collapsible canister 917 in this ready position is shown in FIG.99.

[0421] Once the drive head 937 of the agent injection module 915 isloaded into the driver coupler 185, the controllable driver can then beused to launch the injection member 916 including the hypodermic needle902 and collapsible canister 917 towards and into the patient's tissue903 at a high velocity to a pre-determined depth into the patient's skinor other organ. The velocity of the injection member 916 at the point ofcontact with the patient's skin 903 or other tissue can be up to about10 meters per second for some embodiments, specifically, about 2 toabout 5 mi/s. In some embodiments, the velocity of the injection member916 may be about 2 to about 10 m/s at the point of contact with thepatient's skin 903. As the collapsible canister 917 moves with thehypodermic needle 902, the proximal plate 931 of the collapsiblecanister 917 passes between two latch springs 938 of module body 939that snap in behind the proximal plate 931 when the collapsible canister917 reaches the end of the penetration stroke, as shown in FIG. 100.

[0422] The controllable driver then reverses, applies force in theopposite retrograde direction and begins to slowly (relative to thevelocity of the penetration stroke) retract the hypodermic needle 902.The hypodermic needle 902 slides through the sliding seal 934 of thecollapsible canister 917 while carrying the distal plate 925 of thecollapsible canister with it in a proximal direction relative to theproximal plate 931 of the collapsible canister 917. This relative motionbetween the distal plate 925 of the collapsible canister 917 and theproximal plate 931 of the collapsible canister 917 causes the volume ofthe main chamber 918 to decrease. The decreasing volume of the mainchamber 918 forces the drug or other agent 913 disposed within the mainchamber 918 of the collapsible canister 917 out of the main chamber 918into the inlet port 922 in the shaft 927 of the hypodermic needle 902.The inlet port 922 of the hypodermic needle 902 is disposed within an influid communication with the main chamber 918 of the collapsiblecanister 917 as shown in FIG. 80. The drug or agent then passes throughthe central lumen 923 of the hollow shaft 927 of the hypodermic needle902 and is then dispensed from the output port 912 at the distal end 901of the hypodermic needle 902 into the target tissue 903. The rate ofperfusion of the drug or other agent 913 may be determined by an insidediameter or transverse dimension of the collapsible canister 917. Therate of perfusion may also be determined by the viscosity of the drug oragent 913 being delivered, the transverse dimension or diameter of thecentral lumen 923, the input port 922, or the output port 912 of thehypodermic needle 902, as well as other parameters.

[0423] During the proximal retrograde retraction stroke of thehypodermic needle 902, drug delivery continues until the main chamber918 of the collapsible canister 917 is fully collapsed as shown in FIG.101. At this point, the drive coupler 185 may continue to be retracteduntil the drive head 937 of the hypodermic needle 902 breaks free or thedistal seal 941 between the distal plate 925 of the chamber and thehypodermic needle 902 fails, allowing the drive coupler 185 to return toa starting position. The distal tip 901 of the hypodermic needle 902 canbe driven to a precise penetration depth within the tissue 903 of thepatient using any of the methods or devices discussed above with regardto achieving a desired penetration depth using a controllable driver orany other suitable driver.

[0424] In another embodiment, the agent injection module 915 is loadedinto a ratchet advance mechanism that includes an adjustable or movabledistal stage or surface (not shown) that positions the agent injection915 module relative to a skin contact point or surface 942. In this way,an agent delivery module 915 having a penetration stroke ofpredetermined fixed length, such as shown in FIGS. 99-101, reaches apre-settable penetration depth. The movable stage remains stationaryduring a drug delivery cycle. In a variation of this embodiment, themoveable stage motion may be coordinated with a withdrawal of thehypodermic needle 902 to further control the depth of drug delivery.

[0425] In another embodiment, the latch springs 938 shown in the agentinjection module 915 of FIGS. 99-101 may be molded with a number ofratchet teeth (not shown) that engage the proximal end 932 of thecollapsible canister 917 as it passes by on the penetration stroke. Ifthe predetermined depth of penetration is less than the full stroke, theintermediate teeth retain the proximal end 932 of the collapsiblecanister 917 during the withdrawal stroke in order to collapse the mainchamber 918 of the collapsible canister 917 and dispense the drug oragent 913 as discussed above.

[0426] In yet another embodiment, drive fingers (not shown) are securedto an actuation mechanism (not shown) and replace the latch springs 938.The actuation mechanism is driven electronically in conjunction with thecontrollable driver by a processor or controller, such as the processor60 discussed above, to control the rate and amount of drug deliveredanywhere in the actuation cycle. This embodiment allows the delivery ofmedication during the actuation cycle as well as the retraction cycle.

[0427] Inherent in the position and velocity control system of acontrollable driver is the ability to precisely define the position inspace of the hypodermic needle 902, allowing finite placement of thehypodermic needle in the skin 903 for injection of drugs, vaccines orthe like. Drug delivery can be discrete or continuous depending on theneed.

[0428] FIGS. 102-106 illustrate an embodiment of a cartridge 945 thatmay be used for sampling that has both a lancet cartridge body 946 andan sampling cartridge body 947. The sampling cartridge body 947 includesa plurality of sampling module portions 948 that are disposed radiallyfrom a longitudinal axis 949 of the sampling cartridge body 947. Thelancet cartridge body 946 includes a plurality of lancet module portions950 that have a lancet channel 951 with a lancet 183 slidably disposedtherein. The lancet module portions 950 are disposed radially from alongitudinal axis 952 of the lancet cartridge body 946.

[0429] The sampling cartridge body 947 and lancet cartridge body 946 aredisposed adjacent each other in an operative configuration such thateach lancet module portion 950 can be readily aligned in a functionalarrangement with each sampling module portion 948. In the embodimentshown in FIGS. 102-106, the sampling cartridge body 947 is rotatablewith respect to the lancet cartridge body 946 in order to align anylancet channel 951 and corresponding lancet 183 of the lancet cartridgebody 946 with any of the lancet channels 953 of the sampling moduleportions 948 of the sampling cartridge body 947. The operativeconfiguration of the relative location and rotatable coupling of thesampling cartridge body 947 and lancet cartridge body 946 allow readyalignment of lancet channels 951 and 953 in order to achieve afunctional arrangement of a particular lancet module portion 950 andsampling module portion 948. For the embodiment shown, the relativemotion used to align the particular lancet module portions 950 andsampling module portions 948 is confined to a single degree of freedomvia relative rotation.

[0430] The ability of the cartridge 945 to align the various samplingmodule 948 portions and lancet module portions 950 allows the user touse a single lancet 183 of a particular lancet module portion 950 withmultiple sampling module portions 948 of the sampling cartridge body947. In addition, multiple different lancets 183 of lancet moduleportions 950 could be used to obtain a sample in a single samplingmodule portion 948 of the sampling cartridge body 947 if a fresh unusedlancet 183 is required or desired for each lancing action and previouslancing cycles have been unsuccessful in obtaining a usable sample.

[0431]FIG. 102 shows an exploded view in perspective of the cartridge945, which has a proximal end portion 954 and a distal end portion 955.The lancet cartridge body 946 is disposed at the proximal end portion954 of the cartridge 945 and has a plurality of lancet module portions950, such as the lancet module portion 950 shown in FIG. 103. Eachlancet module portion 950 has a lancet channel 951 with a lancet 183slidably disposed within the lancet channel 951. The lancet channels 951are substantially parallel to the longitudinal axis 952 of the lancetcartridge body 946. The lancets 183 shown have a drive head 198, shaftportion 201 and sharpened tip 196. The drive head 198 of the lancets areconfigured to couple to a drive coupler (not shown), such as the drivecoupler 185 discussed above.

[0432] The lancets 183 are free to slide in the respective lancetchannels 951 and are nominally disposed with the sharpened tip 196withdrawn into the lancet channel 951 to protect the tip 196 and allowrelative rotational motion between the lancet cartridge body 946 and thesampling cartridge body 947 as shown by arrow 956 and arrow 957 in FIG.102. The radial center of each lancet channel 951 is disposed a fixed,known radial distance from the longitudinal axis 952 of the lancetcartridge body 946 and a longitudinal axis 958 of the cartridge 945. Bydisposing each lancet channel 951 a fixed known radial distance from thelongitudinal axes 952 and 958 of the lancet cartridge body 946 andcartridge 945, the lancet channels 951 can then be readily andrepeatably aligned in a functional arrangement with lancet channels 953of the sampling cartridge body 947. The lancet cartridge body 946rotates about a removable pivot shaft 959 which has a longitudinal axis960 that is coaxial with the longitudinal axes 952 and 950 of the lancetcartridge body 946 and cartridge 945.

[0433] The sampling cartridge body 947 is disposed at the distal endportion 955 of the cartridge and has a plurality of sampling moduleportions 948 disposed radially about the longitudinal axis 949 of thesampling cartridge body 947. The longitudinal axis 949 of the samplingcartridge body 947 is coaxial with the longitudinal axes 952, 958 and960 of the lancet cartridge body 946, cartridge 945 and pivot shaft 959.The sampling cartridge body 947 may also rotate about the pivot shaft959. In order to achieve precise relative motion between the lancetcartridge body 946 and the sampling cartridge body 947, one or both ofthe cartridge bodies 946 and 947 must be rotatable about the pivot shaft959, however, it is not necessary for both to be rotatable about thepivot shaft 959, that is, one of the cartridge bodies 946 and 947 may besecured, permanently or removably, to the pivot shaft 959.

[0434] The sampling cartridge body 947 includes a base 961 and a coversheet 962 that covers a proximal surface 963 of the base forming a fluidtight seal. Each sampling module portion 948 of the sampling cartridgebody 947, such as the sampling module portion 948 shown in FIG. 104(without the cover sheet for clarity of illustration), has a samplereservoir 964 and a lancet channel 953. The sample reservoir 964 has avent 965 at an outward radial end that allows the sample reservoir 964to readily fill with a fluid sample. The sample reservoir 964 is influid communication with the respective lancet channel 953 which extendssubstantially parallel to the longitudinal axis 949 of the samplingcartridge body 947. The lancet channel 953 is disposed at the inwardradial end of the sample reservoir 964.

[0435] The lancet channels 953 of the sample cartridge body 947 allowpassage of the lancet 183 and also function as a sample flow channel 966extending from an inlet port 967 of the lancet channel 953, shown inFIG. 106, to the sample reservoir 964. Note that a proximal surface 968of the cover sheet 962 is spatially separated from a distal surface 969of the lancet cartridge body 946 at the lancet channel site in order toprevent any fluid sample from being drawn by capillary action into thelancet channels 951 of the lancet cartridge body 946. The spatialseparation of the proximal surface 968 of the cover sheet 962 from thedistal surface 969 of the lancet cartridge body 946 is achieved with aboss 970 between the two surfaces 968 and 969 that is formed into thedistal surface 969 of the lancet cartridge body as shown in FIG. 105.

[0436] The sample reservoirs 964 of the sampling cartridge body 947 mayinclude any of the sample detection sensors, testing sensors, sensorcontacts or the like discussed above with regard to other samplingmodule embodiments. The cover sheet 962 may be formed of PMMA and haveconductors, sensors or sensor contacts formed on a surface thereof. Itmay also be desirable to have the cover sheet 962 made from atransparent or translucent material in order to use optical sensing ortesting methods for samples obtained in the sample reservoirs. In theembodiment shown, the outer radial location of at least a portion of thesample reservoirs 964 of the sampling cartridge body 967 is beyond anouter radial dimension of the lancet cartridge body 946. Thus, anoptical detector or sensor 971, such as shown in FIG. 105, can detect ortest a sample disposed within a sample reservoir 964 by transmitting anoptical signal through the cover sheet 962 and receiving an opticalsignal from the sample.

[0437] The cartridge bodies 946 and 947 may have features, dimensions ormaterials that are the same as, or similar to, features, dimensions ormaterials of the sampling cartridges and lancet cartridges, or anycomponents thereof, discussed above. The module portions 948 and 950 mayalso have features, dimensions or materials that are the same as, orsimilar to, features, dimensions or materials of the lancet or samplingmodules, or any components thereof, discussed above. In addition, thecartridge 945 can be coupled to, or positioned adjacent any of thedrivers discussed above, or any other suitable driver, in an operativeconfiguration whereby the lancets of the lancet cartridge body can beselectively driven in a lancing cycle. Although the embodiment shown inFIGS. 102-106 allows for alignment of various sampling module portions948 and lancet module portions 950 with relative rotational movement,other embodiments that function similarly are also contemplated. Forexample, lancet module portions, sampling module portions or both, couldbe arranged in a two dimensional array with relative x-y motion beingused to align the module portions in a functional arrangement. Suchrelative x-y motion could be accomplished with position sensors andservo motors in such an alternative embodiment order to achieve thealignment.

[0438] As discussed above for FIGS. 46-48 and illustrated generically inFIG. 107, one embodiment of the present invention may comprise a lancetdriver 1000 configured to exert a driving force on a lancet 1002 andused on a tissue site 234 as seen in FIG. 37. The lancet driver 1000uses a drive force generator 1004 such as, but not limited to, thedevice of FIG. 4, a linear voice coil device 294, or rotary voice coildevice 325 to advance or actuate the lancet along a path 1006 into atissue site 234 (as similarly illustrated in FIGS. 30-41). It should beunderstood that a variety of drive force generators may be used such asvoice coil drive force generators, solenoid drive force generators, orsimilar drive force generators. Spring-based drive force generators orother non-electrical force generators may be used in certain alternativeembodiments where the force generators can deliver the lancet at desiredspeeds while having mechanical dampers, stops, or other apparatus toprovide the desired deceleration that minimizes oscillation of thelancet (see FIG. 68). Additionally, as seen in FIG. 47, the coil doesnot need to be fully surrounded by a magnetically active region.

[0439] A sensor 1008 may be used to detect lancet position along thepath 1006 during the lancing cycle. A suitable sensor may include, butis not limited to, the position sensing mechanism 74, position sensor191, optical position sensor 319, optical position sensor 357, or thelike. A suitable sensor may also include those that can provide lancetposition and sufficient sensor resolution to provide lancet velocityalong the path 1006. As discussed above, the sensor 1008 may bepositioned such as to detect the position of a drive element thatcorresponds to or actuates the lancet (as shown in FIG. 21, element219). The sensor 1008 may also be positioned to detect the position ofthe lancet itself (as shown in FIG. 46, elements 296 and 319).

[0440] Referring now to FIG. 108, a processor 1020 similar to that shownin FIG. 12 (processor 60) or others may be used to support a closedfeedback control loop 1022 as indicated by the arrows, to provide lancetcontrol. The driver 1000 of FIG. 107 may also include a controller orprocessor (not shown). The control of lancet 1002 may involve lancetposition control and may also include lancet velocity control to followa selectable lancet velocity profile or waveform as indicated in FIG.12. In most embodiments, the processor 1020 will be coupled to the driveforce generator 1004 wherein the processor will signal or actuate thegenerator to drive the lancet at various velocities.

[0441] As discussed in regards to FIGS. 6-9, 16-17, and 42, the lancetvelocity profile or waveform may be designed to drive the lancet tominimize pain to a patient while also providing sufficient body fluid orblood yield for sampling purposes. The velocity profile, specifically inelectrically powered force generators, may correspond to the durationand amount of electric current applied to the electrically powered forcegenerators. The velocity profile may also provide for programmabledeceleration profile of the lancet velocity to provide lancet stoppingin the tissue site without a sudden hard stop that increases pain to thepatient. In specific embodiments, the lancet velocity profile may usedwith suitable drive force generators to provide lancet velocitiesbetween about 0.8 to 20.0 meter per second on the penetration stroke andlancet velocities of 0.5 meters per second to less than about 0.02meters per second on the withdrawal stroke.

[0442] Referring to FIGS. 10, 11, and 107, the lancet 1002 may be drivenalong a path towards the tissue site 324, into the tissue site 324, andthen withdrawn from the tissue site 324 (see FIG. 10) to draw body fluidinto a wound channel created by the lancet (see FIG. 11). Although notlimited in this manner, the lancet may follow a one directional linearpath into the tissue site and follow the same linear path out of thetissue site.

[0443] Referring to FIG. 109, a voice coil drive force generator 1030 isshown with a mechanical damper 1032 for providing a controlleddeceleration as the lancet reaches a desired displacement away from thedriver. This mechanical damper 1032 may be similar in concept to onediscussed with FIG. 68, except that the drive portion of the device iselectrically actuated. Other suitable mechanical dampers may includedashpots using air, liquid or gel, electro-dynamic using eddy currentsinduced into a conductor with permanent or electromagnets, mechanicalstops comprising polymer or elastomeric material minimizingoscillations, or a mechanical catch that holds the lancet in positionuntil it is desired to release the lancet for the withdrawal stroke orsome combination of these dampers. It should also be understood that thedamper 1032 may be disposed in a variety of locations on the lancetdriver including coupling to the lancet or to the drive components offorce generator 1030 (shown in phantom).

[0444]FIGS. 110A and 110B show embodiments of the present inventionhaving a drive force generator 1004 and a multiple lancet device 1040such as a bandolier described in FIGS. 96 and 102. The drive forcegenerator 1004 may be, but is not limited to, a voice coil forcegenerator for driving lancet 1042 (FIG. 110B). The multiple lancetdevice or cartridge 1040 is similar to the embodiment of FIG. 93 andallows the user to have multiple lancet events without reloading thedriver with a new lancet for each lancing event. This reduces the numberof steps that a patient performs and thus will reduce the barrier tomore frequent blood glucose testing.

[0445] Referring now to FIG. 111, in one embodiment of the presentinvention, a human interface 1051, such as but not limited to an LCDscreen, may be included with the lancet driver 1050. It shouldunderstood the human interface may provide human readable output, humanrecognizable output (such as flashing indicators, icons, or symbols) orpossible audio signals. The driver 1050 may also include buttons undersoftware control such as one button 1052 for firing or actuating alancet. A first press may turn on the driver 1050 and a second press mayfire or actuate the lancet. In one specific embodiment, presentinvention may use two processors 1054 and 1056 (shown in phantom), theactuator processor 1054 that is fast and high power and the LCD/HumanInterface (HI) processor 1056 that is low power and slower. The HIprocessor 1056 is in sleep mode and runs intermittently to conservepower. The HI processor 1056 controls the power to the actuatorprocessor 1054 as needed. It also is a watchdog timer for the high-speedprocessor so that it will not remain on for long periods of time anddrain the batteries. The communications between these two processors1054 and 1056 uses a few lines and may be, but not necessarily, serialin nature. The communications may use a variety of interface standardsuch as, but not limited to, RS-232, SPI, 1 ²C or a proprietary scheme.The present embodiment may include at least one interface wire andground. In some embodiment, the human interface may provide a variety ofoutputs such as, but not limited to, stick or lancing event number,lancets remaining, time, alarm, profile information, force in laststick/lancing event, or last stick/lancing event time.

[0446] Referring now to FIG. 112, one embodiment of the driver 1050 mayinclude at least one or a plurality of LED lights 1060 to provide alarmsor other information to the user. FIG. 113 show a driver having an audioor sound generator for providing alarm or other information to the user.FIG. 114 shows the driver with a data interface device 1064 (shown inphantom) for allowing data communications with another support devicesuch as, but not limited to, a computer, PDA, a computer network, atemporary storage device, other device for receiving data from thelancet driver. FIG. 115 shows a further embodiment where human interface1051 is on a separate or separable device that is coupled to the driver1050 to provide the human interface feature. It should be understood ofcourse, that the human interface may any of those described herein, suchas those providing video, audio, other signals.

[0447] In one embodiment, the present invention may include one or morebuttons so that the user may control the Human Interface. One or moreoutput display devices such as, but not limited to, individual LED's,arrays of LED's, LCD panels, buzzers, beepers, vibration, may be used bythe user to provide feedback. External communications with other datainterchange devices like personal computers, modems, personal dataassistants, etc. may be provided.

[0448] One function of the human interface is to allow the user toinitiate the cycle of the actuator. To allow user input, the humaninterface may further include but is not limited to, at least onepushbutton, a touch pad independent of the display device, or a touchsensitive screen on the LCD display. Additionally the interface mayallow for other functionality such as an interface that allows the userto control the sampling/pain interface setting, or a device that sensewhether there is a lancet loaded and ready for use, multiplesampling/pain interface protocols that the user can preset for samplingdifferent areas of the body such as the finger versus the forearm.Additionally, a real time clock and one or more alarms the user can setfor reminders of when the next stick is needed. The alarms may beindividually settable with a master enable/disable that affects allalarms to easily suppress them in restaurants and theaters or othersituations where an alarm would be offensive. The alarms can be set forblinking light, sound, and vibration or off. An enhancement would allowan alarm to be enabled for one or more days. This way the users schedulecould be accommodated. For instance an alarm might be set for 10:00 AMfor Monday thru Friday, but turned off Saturday and Sunday in preferenceto an alarm for 11:00 AM on those days. In some embodiments, the HI mayhave a data recorder function. It may accumulate various data forfeedback to the user or another data collection device or network. Someexamples of types of data that might be recorded include: the number oflancets used, the number of sticks for this day, the time and date ofthe last n lancet events, or the interval between alarm and stick,amount of force of the stick, user setting, battery status, etc. The HIprocessor may pass the information to other devices through commonlyavailable data interface devices or interfaces 1064, or optionally aproprietary interface. Some common data interface devices or interfacesinclude but are not limited to: Serial RS-232, modem-interface, USB,HPNA, Ethernet, optical interface, IA, RF interface, Bluetoothinterface, cellular telephone interface, 2 way pager interface, aparallel port interface standard, near field magnetic coupling, or otherRF network transceiver. One use of these interfaces is to move the datato somewhere else so that the user, a doctor, nurse or other medicaltechnician may analyze it. The interfaces may be compatible withpersonal computers, modems, PDAs or existing computer networks.

[0449] While the invention has been described and illustrated withreference to certain particular embodiments thereof, those skilled inthe art will appreciate that various adaptations, changes,modifications, substitutions, deletions, or additions of procedures andprotocols may be made without departing from the spirit and scope of theinvention. For example, the positioning of the LCD screen for the humaninterface may be varied so as to provide the best location for ergonomicuse. The human interface may be a voice system that uses words todescribe status or alarms related to device usage. Expected variationsor differences in the results are contemplated in accordance with theobjects and practices of the present invention. It is intended,therefore, that the invention be defined by the scope of the claimswhich follow and that such claims be interpreted as broadly as isreasonable.

What is claimed is:
 1. A lancet driver configured to exert a drivingforce on a lancet during a lancing cycle and used on a tissue site, saiddriver comprising: a drive force generator for advancing said lancetalong a path into the tissue site; and a sensor configured to detectlancet position along said path during the lancing cycle.
 2. The deviceof claim 1 wherein said sensor detects lancet velocity along said path.3. The device of claim 1 wherein said drive force generator comprises avoice coil drive force generator.
 4. The device of claim 1 wherein saiddrive force generator comprises a rotary voice coil drive forcegenerator.
 5. The device of claim 1 wherein said drive force generatorcomprises a linear voice coil drive force generator.
 6. The device ofclaim 1 wherein the drive force generator comprises a magnetic sourcethat produces a controllable magnetic field in a magnetically activeregion adjacent the magnetic source; a moveable member at leastpartially disposed in the magnetically active region, said member movedby the controllable magnetic field to actuate said lancet.
 7. The deviceof claim 1 wherein said drive force generator uses electricity to createa controllable electromagnetic field for actuating said lancet.
 8. Thedevice of claim 1 further comprising a human interface on a housing ofsaid driver and providing at least one output selected from: sticknumber, lancets remaining, time, alarm, profile information, force inlast stick, or last stick time.
 9. The device of claim 1 furthercomprising a human interface on a housing, said interface selected from:an LED, an LED digit display, or an LCD display.
 10. The device of claim1 further comprising an input device on a housing, said input deviceselected from: at least one pushbutton, a touch pad independent of thedisplay device, or a touch sensitive screen on the LCD display.
 11. Thedevice of claim 1 wherein said drive force generator actuates saidlancet to penetrate to a depth in the tissue site and pause for acontrolled dwell time while in the tissue site, said dwell timesufficient to draw body fluid toward a wound channel created by saidlancet.
 12. The device of claim 1 wherein said drive force generatoruses electricity and is configured to hold said lancet in the tissuesite at a fixed position when electric current is turned off, allowingfor unlimited dwell time in the tissue site.
 13. The device of claim 1wherein said drive force generator has a movable member and a drive coilcreating a magnetic field wherein the drive coil magnetically attractsthe movable member, said drive coil configured to only partiallyencircle side surfaces of said movable member.
 14. The device of claim 1further comprising a mechanical damper disposed to minimize oscillationof the lancet in the tissue site when the lancet reaches an end point ofits penetration stroke into said tissue site.
 15. The device of claim 1a lancet coupler for removably coupling the lancet to said drive forcegenerator.
 16. The device of claim 1 wherein said housing and allelements therein have a combined weight of less than about 0.5 lbs. 17.The device of claim 1 wherein the sensor comprises an incrementalencoder.
 18. The device of claim 1 wherein the sensor comprises a linearoptical incremental encoder.
 19. The device of claim 1 wherein thesensor comprises a rotary optical incremental encoder.
 20. The device ofclaim 1 wherein the sensor comprises a capacitive incremental encoder.21. The device of claim 1 wherein the sensor comprises an opticalencoder and an optical encoder flag secured to the movable member. 22.The device of claim 1 wherein average lancet velocity into the tissuesite differs from average lancet velocity leaving the tissue site. 23.The device of claim 1 wherein said force generator is configured toachieve a withdrawal stroke of the lancet at a lancet velocity of lessthan about 0.02 meter per second.
 24. The device of claim 1 wherein saidforce generator is configured to achieve a penetration stroke of thelancet at a lancet velocity between about 0.8 and 20.0 meter per second.25. The device of claim 1 further comprising a cartridge coupled to thedrive force generator, said cartridge containing a plurality of lancets.26. The device of claim 1 further comprising a processor coupled to thedrive force generator for signaling said generator to change thedirection and magnitude of force exerted on the lancet during thelancing cycle, said sensor communicating with said processor.
 27. Thedevice of claim 26 wherein said processor determines relative positionand velocity of the lancet based on relative position measurements ofthe lancet with respect to time.
 28. The device of claim 26 furthercomprising memory for storage and retrieval of a set of alternativelancing profiles which the processor uses to modulate the drive forcegenerator.
 29. The device of claim 26 wherein the processor modulatesthe lancet driver by comparing an actual profile of the lancet to theprofile and maintaining a preset error limit between the actual profileand the profile.
 30. The device of claim 26 wherein the processoroptimizes said phases of a lancet velocity profile based on informationentered by a user of the lancing device.
 31. The device of claim 26wherein the processor calculates an appropriate lancet diameter andgeometry to collect a blood volume required by a user.
 32. The device ofclaim 26 wherein said processor has logic for learning and recordingcharacteristics of said tissue site to optimize control of lancetvelocity and lancet position in a manner that minimizes pain to thepatient while drawing body fluid for sampling.
 33. The device of claim 1wherein a processor actuates said drive force generator to drive thelancet at velocities in time that follow a selectable lancing velocityprofile said selectable lancing velocity profile is selected from a setof alternative lancing velocity profiles having characteristic phasesfor lancet advancement and retraction.
 34. The device of claim 33wherein the lancing velocity profile is selectable by a user of thelancing device.
 35. The device of claim 33 wherein said lancing velocityprofile provides a lancet withdrawal velocity sufficiently slow to allowblood flowing from punctured blood vessels to flow into a wound channelin the tissue site created by the lancet, to follow the lancet out ofthe wound channel, and flow to a skin surface.
 36. The device of claim33 wherein said velocity profile includes a lancet deceleration phase,after said lancet penetrates said tissue site and prior to withdrawalfrom said tissue site, wherein said lancet velocity follows aprogrammable deceleration profile having said lancet stopping in thetissue site without a sudden hard stop.
 37. The device of claim 33wherein the lancing velocity profile is selected by the lancing devicebased on optimization of lancing parameters from information obtained inprevious lancing events.
 38. The device of claim 37 wherein saidprocessor optimizes said velocity profile for subsequent lancing basedupon success of obtaining a blood sample from said user in previouslancing events.
 39. The device of claim 37 wherein said processoroptimizes said velocity profile for subsequent lancing based upon bloodvolume obtained from said user in previous lancing events.
 40. Thedevice of claim 37 wherein said processor optimizes said velocityprofile for subsequent lancing based upon elastic tenting associatedwith skin deformation in previous lancing events.
 41. The device ofclaim 37 wherein said lancet penetrating to a depth in the tissue sitebased on impedance measurements from a distal portion of the lancet insaid tissue site.
 42. A lancet driver configured to exert a drivingforce on a lancet used at a tissue site during a lancing cycle, saiddevice comprising: a voice-coil, drive force generator; and a processorcoupled to the drive force generator capable of changing the directionand magnitude of force exerted on the lancet during the lancing cycle; aposition sensor configured to detect lancet position during the lancingcycle.
 43. The device of claim 42 wherein said voice coil comprises acylindrical coil encircling a movable magnet.
 44. The device of claim 42wherein said voice coil comprises a linear flat coil.
 45. The device ofclaim 42 wherein said drive force generator comprises a rotary voicecoil drive force generator.
 46. The device of claim 42 wherein saiddrive force generator comprises a linear voice coil drive forcegenerator.
 47. The device of claim 42 wherein the drive force generatorcomprises a magnetic source that produces a controllable magnetic fieldin a magnetically active region adjacent the magnetic source; a moveablemember at least partially disposed in the magnetically active region,said member moved by the controllable magnetic field to actuate saidlancet.
 48. The device of claim 42 wherein said drive force generatoruses electricity to create a controllable electromagnetic field foractuating said lancet.
 49. The device of claim 42 further comprising ahuman interface on a housing of said driver and providing at least oneoutput selected from: stick number, lancets remaining, time, alarm,profile information, force in last stick, or last stick time.
 50. Thedevice of claim 42 further comprising a human interface on a housing,said interface selected from: an LED, an LED digit display, or an LCDdisplay.
 51. The device of claim 42 further comprising an input deviceon a housing, said input device selected from: one or more pushbuttons,a touch pad independent of the display device, or a touch sensitivescreen on the LCD display.
 52. The device of claim 42 wherein said driveforce generator actuates said lancet to penetrate to a depth in thetissue site and pause for a controlled dwell time while in the tissuesite, said dwell time sufficient to draw body fluid toward a woundchannel created by said lancet.
 53. The device of claim 42 wherein saiddrive force generator uses electricity and is configured to hold saidlancet in the tissue site at a fixed position when electric current isturned off, allowing for unlimited dwell time in the tissue site. 54.The device of claim 42 wherein said drive force generator holds saidlancet at a fixed position against tenting force from said tissue sitewithout contacting a mechanical stop.
 55. The device of claim 42 whereinsaid drive force generator has a movable member and a drive coilcreating a magnetic field wherein the drive coil magnetically attractsthe movable member, said drive coil configured to only partiallyencircle said movable member.
 56. The device of claim 42 a mechanicaldamper disposed to minimize oscillation of the lancet in the tissue sitewhen the lancet reaches an end point of its penetration stroke into saidtissue site.
 57. The device of claim 42 a lancet coupler for removablycoupling the lancet to said drive force generator.
 58. The device ofclaim 42 wherein said housing and all elements therein have a combinedweight of less than about 0.5 lbs.
 59. The device of claim 42 whereinthe sensor comprises an incremental encoder.
 60. The device of claim 42wherein the sensor comprises a linear optical incremental encoder. 61.The device of claim 42 wherein the sensor comprises a rotary opticalincremental encoder.
 62. The device of claim 42 wherein the sensorcomprises a capacitive incremental encoder.
 63. The device of claim 42wherein the sensor comprises an optical encoder and an optical encoderflag secured to the movable member.
 64. The device of claim 42 whereinaverage lancet velocity into the tissue site differs from average lancetvelocity leaving the tissue site.
 65. The device of claim 42 whereinsaid force generator is configured to achieve a withdrawal stroke of thelancet at a lancet velocity of 0.5 meters per second to less than about0.02 meter per second.
 66. The device of claim 42 wherein said forcegenerator is configured to achieve a penetration stroke of the lancet ata lancet velocity between about 0.8 and 20.0 meter per second.
 67. Thedevice of claim 42 further comprising a cartridge coupled to the driveforce generator, said cartridge containing a plurality of lancets. 68.The device of claim 42 further comprising a processor coupled to thedrive force generator for signaling said generator to change thedirection and magnitude of force exerted on the lancet during thelancing cycle, said sensor communicating with said processor.
 69. Thedevice of claim 68 wherein said processor determines relative positionand velocity of the lancet based on relative position measurements ofthe lancet with respect to time.
 70. The device of claim 68 furthercomprising memory for storage and retrieval of a set of alternativelancing profiles which the processor uses to modulate the drive forcegenerator.
 71. The device of claim 68 wherein the processor modulatesthe lancet driver by comparing an actual profile of the lancet to theprofile and maintaining a preset error limit between the actual profileand the profile.
 72. The device of claim 68 wherein the processoroptimizes said phases of a lancet velocity profile based on informationentered by a user of the lancing device.
 73. The device of claim 68wherein the processor calculates an appropriate lancet diameter andgeometry to collect a blood volume required by a user.
 74. The device ofclaim 68 wherein said processor has logic for learning and recordingcharacteristics of said tissue site to optimize control of lancetvelocity and lancet position in a manner that minimizes pain to thepatient while drawing body fluid for sampling.
 75. The device of claim42 wherein a processor actuates said drive force generator to drive thelancet at velocities in time that follow a selectable lancing velocityprofile said selectable lancing velocity profile is selected from a setof alternative lancing velocity profiles having characteristic phasesfor lancet advancement and retraction.
 76. The device of claim 75wherein the lancing velocity profile is selectable by a user of thelancing device.
 77. The device of claim 75 wherein said lancing velocityprofile provides a lancet withdrawal velocity sufficiently slow to allowblood flowing from punctured blood vessels to flow into a wound channelin the tissue site created by the lancet, to follow the lancet out ofthe wound channel, and flow to a skin surface.
 78. The device of claim75 wherein said velocity profile includes a lancet deceleration phase,after said lancet penetrates said tissue site and prior to withdrawalfrom said tissue site, wherein said lancet velocity follows aprogrammable deceleration profile having said lancet stopping in thetissue site without a sudden hard stop.
 79. The device of claim 75wherein the lancing velocity profile is selected by the lancing devicebased on optimization of lancing parameters from information obtained inprevious lancing events.
 80. The device of claim 79 wherein saidprocessor optimizes said velocity profile for subsequent lancing basedupon success of obtaining a blood sample from said user in previouslancing events.
 81. The device of claim 79 wherein said processoroptimizes said velocity profile for subsequent lancing based upon bloodvolume obtained from said user in previous lancing events.
 82. Thedevice of claim 79 wherein said processor optimizes said velocityprofile for subsequent lancing based upon elastic tenting associatedwith skin deformation in previous lancing events.
 83. The device ofclaim 79 wherein said lancet penetrating to a depth in the tissue sitebased on impedance measurements from a distal portion of the lancet insaid tissue site.
 84. A lancet driver configured to exert a drivingforce on a lancet during a lancing cycle and used on a tissue site, saiddevice comprising: a voice-coil, drive force generator; and a processorcoupled to the drive force generator capable of changing the directionand magnitude of force exerted on the lancet during the lancing cycle;wherein said processor actuates said drive force generator to drive thelancet at velocities in time that follow a selectable lancing velocityprofile.
 85. The device of claim 84 wherein said drive force generatorcomprises a rotary voice coil drive force generator.
 86. The device ofclaim 84 wherein said drive force generator comprises a linear voicecoil drive force generator.
 87. The device of claim 84 wherein the driveforce generator comprises a magnetic source that produces a controllablemagnetic field in a magnetically active region adjacent the magneticsource; a moveable member at least partially disposed in themagnetically active region, said member moved by the controllablemagnetic field to actuate said lancet.
 88. The device of claim 84wherein said drive force generator uses electricity to create acontrollable electromagnetic field for actuating said lancet.
 89. Thedevice of claim 84 further comprising a human interface on a housing ofsaid driver and providing at least one output selected from: sticknumber, lancets remaining, time, alarm, profile information, force inlast stick, or last stick time.
 90. The device of claim 84 furthercomprising a human interface on a housing, said interface selected from:an LED, an LED digit display, or an LCD display.
 91. The device of claim84 further comprising an input device on a housing, said input deviceselected from: one or more pushbuttons, a touch pad independent of thedisplay device, or a touch sensitive screen on the LCD display.
 92. Thedevice of claim 84 wherein said drive force generator actuates saidlancet to penetrate to a depth in the tissue site and pause for acontrolled dwell time while in the tissue site, said dwell timesufficient to draw body fluid toward a wound channel created by saidlancet.
 93. The device of claim 84 wherein said drive force generatoruses electricity and is configured to hold said lancet in the tissuesite at a fixed position when electric current is turned off, allowingfor unlimited dwell time in the tissue site.
 94. The device of claim 84wherein said drive force generator holds said lancet at a fixed positionagainst tenting force from said tissue site without contacting amechanical stop.
 95. The device of claim 84 wherein said drive forcegenerator has a movable member and a drive coil creating a magneticfield wherein the drive coil magnetically attracts the movable member,said drive coil configured to only partially encircle said movablemember.
 96. The device of claim 84 a mechanical damper disposed tominimize oscillation of the lancet in the tissue site when the lancetreaches an end point of its penetration stroke into said tissue site.97. The device of claim 84 a lancet coupler for removably coupling thelancet to said drive force generator.
 98. The device of claim 84 whereinsaid housing and all elements therein have a combined weight of lessthan about 0.5 lbs.
 99. The device of claim 84 wherein the sensorcomprises an incremental encoder.
 100. The device of claim 84 whereinthe sensor comprises a linear optical incremental encoder.
 101. Thedevice of claim 84 wherein the sensor comprises a rotary opticalincremental encoder.
 102. The device of claim 84 wherein the sensorcomprises a capacitive incremental encoder.
 103. The device of claim 84wherein the sensor comprises an optical encoder and an optical encoderflag secured to the movable member.
 104. The device of claim 84 whereinaverage lancet velocity into the tissue site differs from average lancetvelocity leaving the tissue site.
 105. The device of claim 84 whereinsaid force generator is configured to achieve a withdrawal stroke of thelancet at a lancet velocity of 0.5 meters per second to less than about0.02 meter per second.
 106. The device of claim 84 wherein said forcegenerator is configured to achieve a penetration stroke of the lancet ata lancet velocity between about 0.8 and 20.0 meter per second.
 107. Thedevice of claim 84 further comprising a cartridge coupled to the driveforce generator, said cartridge containing a plurality of lancets. 108.The device of claim 84 further comprising a processor coupled to thedrive force generator for signaling said generator to change thedirection and magnitude of force exerted on the lancet during thelancing cycle, said sensor communicating with said processor.
 109. Thedevice of claim 108 wherein said processor determines relative positionand velocity of the lancet based on relative position measurements ofthe lancet with respect to time.
 110. The device of claim 108 furthercomprising memory for storage and retrieval of a set of alternativelancing profiles which the processor uses to modulate the drive forcegenerator.
 111. The device of claim 108 wherein the processor modulatesthe lancet driver by comparing an actual profile of the lancet to theprofile and maintaining a preset error limit between the actual profileand the profile.
 112. The device of claim 108 wherein the processoroptimizes said phases of a lancet velocity profile based on informationentered by a user of the lancing device.
 113. The device of claim 108wherein the processor calculates an appropriate lancet diameter andgeometry to collect a blood volume required by a user.
 114. The deviceof claim 108 wherein said processor has logic for learning and recordingcharacteristics of said tissue site to optimize control of lancetvelocity and lancet position in a manner that minimizes pain to thepatient while drawing body fluid for sampling.
 115. The device of claim84 wherein a processor actuates said drive force generator to drive thelancet at velocities in time that follow a selectable lancing velocityprofile said selectable lancing velocity profile is selected from a setof alternative lancing velocity profiles having characteristic phasesfor lancet advancement and retraction.
 116. The device of claim 1 15wherein the lancing velocity profile is selectable by a user of thelancing device.
 117. The device of claim 115 wherein said lancingvelocity profile provides a lancet withdrawal velocity sufficiently slowto allow blood flowing from punctured blood vessels to flow into a woundchannel in the tissue site created by the lancet, to follow the lancetout of the wound channel, and flow to a skin surface.
 118. The device ofclaim 115 wherein said velocity profile includes a lancet decelerationphase, after said lancet penetrates said tissue site and prior towithdrawal from said tissue site, wherein said lancet velocity follows aprogrammable deceleration profile having said lancet stopping in thetissue site without a sudden hard stop.
 119. The device of claim 115wherein the lancing velocity profile is selected by the lancing devicebased on optimization of lancing parameters from information obtained inprevious lancing events.
 120. The device of claim 119 wherein saidprocessor optimizes said velocity profile for subsequent lancing basedupon success of obtaining a blood sample from said user in previouslancing events.
 121. The device of claim 119 wherein said processoroptimizes said velocity profile for subsequent lancing based upon bloodvolume obtained from said user in previous lancing events.
 122. Thedevice of claim 119 wherein said processor optimizes said velocityprofile for subsequent lancing based upon elastic tenting associatedwith skin deformation in previous lancing events.
 123. The device ofclaim 119 wherein said lancet penetrating to a depth in the tissue sitebased on impedance measurements from a distal portion of the lancet insaid tissue site.
 124. A body fluid sampling device configured to exerta driving force on a lancet during a lancing cycle and used on a tissuesite, said device comprising: a drive force generator suitable foractuating the lancet along said path towards the tissue site, into thetissue site, and then back out of the tissue site, said lancetpenetrating to a depth in the tissue site sufficient to draw body fluidfrom the tissue site for sampling; a closed feedback control loop forcontrolling said drive force generator based on position and velocity ofthe lancet.
 125. The device of claim 124 further comprising a processorfor regulating the electric drive mechanism to actuate the lancet atvelocities conforming with said selectable lancing velocity profile.126. The device of claim 124 wherein said closed feedback control loopdirects said electric drive mechanism to stop the lancet in the tissuesite without oscillation of the lancet and lancet position in the tissuesite.
 127. A body fluid sampling device for use at a tissue site on apatient, said device comprising: a drive force generator; and aprocessor coupled to the drive force generator capable of changing thedirection and magnitude of force exerted on the lancet during thelancing cycle; a position sensor configured to detect lancet positionduring the lancing cycle; wherein said drive force generator actuatessaid lancet along a one directional, linear path towards the tissuesite, into the tissue site, and then back out of the tissue site, saidlancet penetrating to a depth in the tissue site and pauses for acontrolled dwell time while in the tissue site, said dwell timesufficient to draw body fluid toward a wound channel created by saidlancet.
 128. The device of claim 127 further comprising a processor forregulating the drive force generator to actuate the lancet at velocitiesconforming with a selectable lancing velocity profile and providing forsaid controlled dwell time.
 129. The device of claim 127 wherein saiddrive force generator is configured to hold said lancet in the tissuesite at a fixed position when electric current is turned off andallowing for unlimited dwell time in the tissue site.
 130. A body fluidsampling device for use at a tissue site on a patient, said devicecomprising: a voice-coil, drive force generator; and a processor coupledto the drive force generator capable of changing the direction andmagnitude of force exerted on the lancet during the lancing cycle; aposition sensor configured to detect lancet position during the lancingcycle; a damper disposed to minimize oscillation of the lancet in thetissue site when the lancet reaches an end point of its penetrationstroke into said tissue site.
 131. The device of claim 130 wherein saidend point of the penetration stroke is adjustable based on bloodsampling success.
 132. A method for sampling body fluid from a tissuesite, said method comprising: driving a lancet along a path into thetissue site; using a sensor to detect lancet position along said pathinto the tissue site.
 133. The device of claim 132 further comprisingstopping said lancet in said tissue site for a controlled dwell time toallow body fluid to gather.
 134. The device of claim 132 furthercomprising stopping said lancet in accordance with a decelerationvelocity profile minimizing oscillation of said lancet in the tissuesite.
 135. The device of claim 132 wherein said using step comprisesdetecting lancet velocity.
 136. The device of claim 132 furthercomprising decelerating said lancet by using a mechanical damper tominimize oscillation.
 137. The device of claim 132 further comprisingwithdrawing said lance from said tissue site along a wound channelcreated during the driving step.
 138. The device of claim 132 whereinsaid driving step uses a movable member moved by a controlled magneticfield to actuate said lancet.
 139. The device of claim 132 wherein saiddriving step uses a voice coil force generator having a movable membermoved by a controlled magnetic field to actuate said lancet.
 140. Thedevice of claim 132 wherein said driving step comprises actuating saidlancet at velocities that follow a selectable lancing velocity profile.141. The device of claim 132 further comprising withdrawing said lancetat lancet velocities sufficiently slow to allow body fluid to flow intoa wound channel in the tissue site created by said lancet.
 142. A methodfor sampling body fluid from a tissue site, said method comprising:driving a lancet along a path into the tissue site using closed loopfeedback to control lancet velocity to follow a selectable lancingvelocity profile.
 143. The device of claim 142 wherein said wherein saidselectable lancing velocity profile has average lancet velocity into thetissue site being greater than average lancet velocity leaving saidtissue site.
 144. The device of claim 132 wherein said driving step usesa movable member moved by a controlled magnetic field to actuate saidlancet.